Correction. We live in a system that *rewards* that. The infrastructure and system itself expects us to drive everywhere (because it's either faster or literally at all possible), eat overprocessed food (because it's tastier (literally designed to be hyper-palpable) and faster), and to work for absurd hours.
If you somehow have spoons after all that, then you're expected to workout, etc, to gain the additional benefits; but the systems in play do not facilitate that, at all.
Luckily there's a precise term from economics we can use here to split the difference: Opportunity cost. I can certainly concede that in some people's lives the opportunity cost to working out is higher. In some lives you make a lot more money per hour worked than you do working out, and so it's not a surprise more people on the margin in those situations choose the former over the latter. If you dislike even having that option on the table, the good news is you can move to someplace where you make less money, and then that opportunity cost will go down, because working out is pretty much the same wherever you go.
One more sophisticated take of course is to claim people don't really know what's good for them, and they discount the true value of working out far too heavily. (s/working out/eating less/g, or whatever other health promoting difficult activity you wish to sub in here.) But, if we're going to claim that -- which is actually pretty reasonable -- then why would we consider a miracle drug that seems to directly counteract that irrational discounting a bad thing? That should be a godsend.
When I’m really feeling the stress, even though I will tell myself at that time to just hang on and hit the gym later, the food is that much more of an instant fix that it wins out more often than not.
I’m sure that’s not just the actual food itself, but also the easy availability of it, and probably subliminal cultural factors such as advertising. But partly, yeah, it’s that my ancestors evolved to love eating when they had food, and their gift to me is that same desire in a world of endless plenty.
There is, in fact, already an enormous, fully endogenous incentive to do those things. The fact many people are not keeping in shape (myself included) suggests the allure of food really is just that appealing.