No idea the circumstances, but I can see one reason to buy dinner before the move. After buying a house you’re often pretty strapped for cash, so maybe you buy dinner when you have the cash beforehand, rather than stalling the friends for 2 weeks to have the cash. Unrelated to the OP, but a thought in some cases.
The tried and true, classic, always-works tack is to announce a free keg for anyone that helps load the U-Haul. Think of the guys you know that are up for “free” beer and they’re usually the kinds that have enough mass to move some heavy shit. Less than $70, in most cases, and you have a crew that will have the truck loaded before the keg is dry. No matter how much stuff you have. Just have your better half play bartender and lay the classic guilt-look on anyone not pulling his weight.
And I call bullshit on the age angle. Granted I’m 33 so by no means rate as a geezer, but if you’re under 50 you can help a friend move. And if it’s a friend, the keg shouldn’t be the dealbreaker. You help a buddy out. Dinner or beer is a bonus. I just cannot fathom not helping a friend out. Unless he’s banking serious coin and just wants to be cheap. In which case it better 2 kegs.
You do have the upper hand, though. If they are really friends that you plan on keeping, follow my 12 month rule. You’ve bought them dinner for a job they never performed. For the next 12 months you don’t have to help them in anything, even if it’s something as mundane as grabbing a socket for them while they’re under the car changing the oil. Or recovering their system from bad porn. Or getting the fire extinguisher when the deep-fried turkey ignites. It’s a bit liberating if you look at it in the right light.
And it sucks you can’t count on help a friend promised. I’ve been there, I know what it’s like. If I was anywhere near your neck of the woods I’d offer a hand. I love a moving party, provided there’s beer. Small consolation, but there it is.
By the way, while I don’t mind helping friends, I’ve already told my wife we are either hiring movers next time, or we’re including all our shit in the sale of the place. It seems that helping someone move is a bit recreational to me, but moving my own crap again is just too damn tedious for me to ever do again.
Whatever happens, hope it turns out, and congrats on the new house!