Just as a thought experiment, taking care of an aging population boom in a contracting economy seems like a significant challenge. A planned economy would have more tools to deal with that, but it isn't trivial or unique to capital. You're going to need to spend a lot of resources on caregiving, medical services, housing, not to mention that your food production and manufacturing is gonna have to be really efficient because your non-caregiving labor force will be smaller than otherwise.
I'm sure some countries have done that well, I just don't know enough to know which ones and how they did it.
China is an example of a massively expanding economy and expanding population in which they took steps to slow down like one child policy, which seems on the whole to have sidestepped the problem. China's population seems ready to decline now so it will be interesting to see how that goes and what they come up with.
At risk of a fatphobia struggle session, there are legitimate lifestyle and health reasons that one might want to lose weight. It's a crime that these drugs are being price gouged.
I've read that maintaining weight loss after stopping the drugs can be a challenge, but it does let you skip over the part where you feel hungry the entire time you're losing weight.
The bottom line for me is that these drugs are a rare weapon against the weaponized junk food we are inundated with every time we go to the grocery store.