I live in a double wide trailer. Don’t get me wrong - I like my house a lot.
But living with my mentally ill mother? Seeing her every day? No way. Or my alcoholic father I haven’t spoken to in six years? Not likely.
That I don’t get. And I too have a strained, pretty estranged relationship with my mentally ill parents.
I’m crammed into an apartment that provides around half, maybe less, of the space I really want. I really, really want to get into a house - limited only by the terrible market and the fact I want to retain a short commute (for when commutes start back up).
However I cannot ignore the fact that this arrangement has a likely outcome of making my kitchen unlivable, due to the noise and chaos alone. Plus it seems likely that switching to this arrangement would worsen my relations with my family - even if we ignore the fact that some of them will suddenly have a thousand-mile commute, constant contact isn’t necessarily a good thing for familial relations. The only thing that makes this vaguely palatable would be that each family would essentially be in separate houses - you couldn’t pay me to move back in with my parents and be subject to my dad’s draconic curfew, for example. And as noted above, there is no chance in hell I’m going to let my nieces and nephews past the threshold to have their way with my many possessions and collections.
If the arrangement would be for all the members of my family to be in separate houses lined up in a row next to each other, I’d take this in a heartbeat. (As long as I’m not the one with a thousand mile commute.) But giving everybody an open backdoor into my house (if I ever forget to lock the door to my kitchen) is a bridge too far. Good fences do good neighbors make.
I like my home all right, though certainly a far cooler house would be a plus.
However, I can guarantee that having to be under the same roof as my in-laws (and having to share certain rooms with them, on a permanent basis, as was specifically laid out in the OP) would make even the uber-cool house intolerable. This isn’t “you have a massive estate, and they’re a mile away in a different structure.”
I get stabby enough when I have to spend a full day with them.
I think there is a distinct paucity of imagination here. The OP laid it out:
I was thinking of a 100,000 square foot mansion with a kitchen that covers a tennis court sized area with multiples of every appliance and accoutrements. A large live-in household staff numbering in the ten’s of people (drivers, maids, cooks, gardeners, etc.), including support for aged and infirm relatives.
Are some of you telling me that living is such a house, with the only upkeep you have to do is the things you like to do, where you can be in a larger set of rooms than you currently live in, shut away from everyone is beyond your imagination? The limit of “anything goes” is 3 bedrooms and 2 baths?
I’m happy with what I have, I guess. And certainly not willing to sacrifice my mental health for material gain.
My living conditions are really crammed, not because I live in a tiny house, but because I have lots and lots of stuff that takes up plenty of space. I’m a homebody with myriad varied interests and projects. Everything outside daily city living routines that I do is either a searching / unpacking / room clearing chore on top of the actual activity, or an outright impossibility, due to lack of space. Lots of extra room would solve this.
Come fantasy time, and I’d have, and definitely use a weight room, a library, a multimedia room, a woodshop, a metal shop, an indoor shooting range, butchering facilities, leather tanning facilities, flintknapping facilities, a 3D archery course, and an outdoor shooting range.
Yeah, this isn’t a massive estate, but this is, if wanted, an impossibly large house - remember: the coolest house on Earth! This would mean that my relatives have relative houses all to themselves under the same roof as do I. In effect they’re a mile away, just not when it’s kitchen time.
ETA: what peccavi said.
And, as I have now said three times, that is the non-negotiable dealbreaker for me. As I said, my in-laws are intolerable, and the only reason that I have not already burned my bridges with them is for the sake of my wife (who loves her family, though she recognizes that they are often irrational and behave horribly).
For the past decade or more, I’ve spent the past decade or more limiting my interactions with them as much as I can, specifically because I know that the more I’m around them, the higher the odds that I will finally have had it with them, blow up, and say something that cannot be taken back, permanently fracturing things, to my wife’s detriment.
Would such a setup work for you? If it does, awesome for you! It would not work for me, and I know it.
Negative Ghost Rider, my pattern is full.
Tripler
Fly-bys are scheduled months in advance.
Feh, I messed up my editing. Ingore the repetitive phrase. 
Nobody’s a mile off, because nobody lives a mile away from their kitchen. And if you’re positing that the kitchen is a gigantic stadium a mile across where everybody has their own little oasis of supplies and appliances right against their door, I’d say that’s 1) absurd, and 2) fighting the hypothetical, because nobody would walk the mile to interact while waiting for their burrito to cook.
I presume that the kitchen is large but not so large that it takes more than a minute to cross it. Which means that while I’m rooting around in the begbert2 fridge for my burritos, one of my sister’s free-range kids could run past, through my door, and start wrecking the place. (And I’m only barely exaggerating - stuff gets broken a lot at their place. I think they’ve even lost a few TVs.)
And, sure, I could carefully lock my kitchen door behind me whenever I want to grab a bag of chips, but that’s not exactly going to endear me to my family. Tensions will rise, because while I’m cool with them letting their kids be hooligans, I’m not cool letting their hooligans come with a hundred feet of my house or possessions. And honestly I’m not tactful enough to be subtle about it.
This. A thousand times. (What spice weasel said! I screwed up the quote thing!)
Their company is damaging to my mental health. My dream home IS somewhere they’re NOT !
I made somewhat nice ish, occasionally, well into my fifties. A traumatic family event saw us all in close quarters for a day and a half. It did not bring out the best in them. When we parted I knew, I would very likely never see these people again.
Life is too short to spend even a minute with damaging people.
Sigh. The “In effect” in my reply meant figuratively. Of course the house isn’t a mile + long. But if someone lives 20 rooms and five corridores and a dozen doors and some 100 meters away from me, the effect is not much different from having a mile of wide open space between us. I would never have to see or even hear those people, outside the stated kitchen time.
Okay, but that presumes that what happens in the kitchen stays in the kitchen. When dealing with children under the age of five, you’re doing pretty good to keep them from wandering out the front door into the street.
My sister lets her kids wander freely throughout their neighborhood, and the kids there reportedly wander into and out of each others houses without invitation. They’re also taught that nobody has ownership over things - if somebody wants to play with your toy you have to let them, in the name of sharing. So I have no confidence that these kids (who will be going into the kitchen, have no doubt - that’s where the snacks are) will not consider the siren song of my legos and transformers to be an open invitation.
Why not assign each kid a staff member to corral and keep them in line. Trained professional child care workers. Remember, the OP said:
Because they’re not my kids, and imprisoning my siblings’ children against their will would worsen familial relations even faster than slamming the door in their faces would?
You get to live in the coolest house on earth, BUT your relatives live with you…
… hence, no longer the coolest house on earth.
I mean, imagine Frank Lloyd Wright’s Falling Water.…
…with Ned Flanders and Hank Hill living there.
You speak much wisdom. I didn’t like fallingwater as a place to live when I first saw it on the internet, even though it looked good from the outside. Then I took a tour and my opinion changed. I still wouldn’t want to live there … but it’s a really great place for the weekends. One weekend. Not 52 weekends. I wouldn’t want my relatives having to go to the main building to cook their breakfast every day. I don’t remember if the attached buildings had their own kitchens but I would have hoped that they did had I owned it.
Coolest house on earth must mean lots of huge rooms, tunnels and serene surroundings which means even if I really resent my relatives then there is a retreat