Broadly, the downside is paying for services you don’t need. The single person who buys a club-cab 4-door pickup truck but who never carries friends or outsized cargo is another example of buying capabilities you don’t need.
I dealt with the Independent Living (“IL”) place for my late aged MIL. I’ve not lived in one myself. While my late first wife was becoming increasingly infirm we discussed the possibility that if her mobility challenges got bad enough while she was still sorta capable otherwise we might move her, and therefore me, into such a place. As well we had a standing plan that if I became dead or disabled myself, she would move into such a place promptly to get the support I was no longer able to provide. In her case I remained healthy and her mind was fine and her mobility was adequate up until her end so we never needed to execute those plans.
So for somebody who’s never lived or worked in such a place I’ve probably thought more about it than most. And with MIL spent more time there than most as well.
My own view is the critical thing IL provides is 3 square meals a day and a nurse on-station plus folks to check on you every day. As we age, our ambition is one of the things to go. Old folks slowly starve themselves to death because making nutritious meals becomes first “more effort than I care to put into it” then soon enough it’s “more effort than I can put into it”. As does grocery shopping. Soon they’re living on “tea and toast” then malnutrition sets in. Which exacerbates all their other physical and mental ailments. etc. IL stops all that. Its the ginormous Easy Button for folks for whom getting dressed, wielding a fork, and reading or TV watching is about the limit of their daily ambitions. Even though they may have more capabilities.
In your house now you have a bunch of outside services contracted to do stuff. And armed with an on-call handyman you could remain there a long time as you suggest. What I found about those service arrangements when I was a homeowner was they did not stay arranged. Gardeners would move away, turn to drugs and become useless, or whatever. Housekeepers had high turnover. The roofer I used 5 years ago had gone out of business when i needed warrantee service. etc. etc.
My vendors might be fixed, but they don’t stay fixed. So you have a continuous flux of tasks to locate and retain help. Which gets harder as we get older. And, sadly, increases the likelihood that you’ll stumble upon a crook who’ll take advantage of your depleting condition.
My solution now, as a hale 65yo, is I moved to a nice apartment in a large professionally run building. I sold my residence and invested the proceeds. I pay a bit more per month to live in fewer square feet, but the earnings from the house sale proceeds, plus the expenses and taxes and mortgage payments foregone, collectively cover that increment easily.
Now I am responsible for exactly zero except feeding myself and housework. If a lightbulb burns out I call maintenance. The fixtures in the ceiling are their responsibility not mine. I have far fewer invoices to pay every month, and no suppliers to deal with besides the local electric company & phone/internet company. Neither of which are going to move away or become drug-addicted.
By choosing to live urban I can affordably and conveniently switch to uber when I can’t drive, or to a power-scooter when I can’t walk. I don’t make use of delivery services for restaurant meals nor groceries, but Amazon does most of my hard-goods shopping for me today. Not because I can’t shop; I was at a big mall earlier today. But just because Amazon is so damned convenient = low ambition required.
All those local delivery services are available once I decide I want them, whether for infirmity or mere convenience. Plenty of young people here live on Door Dash from local restaurants and have Instacart or wal*mart do their grocery shopping and drop it at their door.
A person in my or your position can create your own “Easy-enough” button without going whole hog into IL. The residents there are decidedly decrepit. You can live there and sorta ignore them, but that’s less than ideal.
I view my situation as a good halfway house until I’m real raggedy. I may buy-in a maid service at some point, and I will end up with delivered groceries and hot meals. But shortly before even that simple life gets too hard for me, I’ll be calling a local IL place to make a move.
There’s another Doper who’s a bit older than you and moved to IL with his wife a year(?) ago. IIRC it was a bit more her infirmities than his that drove the decision. He will certainly have some useful insights if he’s willing to share. @Chefguy?