There isn't one now, fine. But why shouldn't we be trying to invent one?

You're welcome to try. If you succeed even partially then you'll be a billionaire. But these are complex biological systems and it's a tremendously difficult problem. I guarantee you that within our lifetimes we won't see a safe and effective drug that produces health benefits equivalent to frequent hard exercise. Many of those benefits come from the physical motion which helps to keep blood and lymph circulating normally so I can't see any way to put that in a pill.

That's the way to make sure you're unhappy. Exercise, and life, should never be about "embracing the suck". Finding ways to exercise that you enjoy and that can fit in your schedule makes it a default state rather than something you avoid.

No, you're just completely wrong. That doesn't make people unhappy. Where did you come up with such a ridiculous notion? Do you lack experience in the real world? Have you never played competitive sports?

Idk I think I'm completely right, exercise is supposed to be fun and trying to willpower your way through something you hate is a surefire way to be unhappy

No, you're just completely wrong. Life in general isn't supposed to be fun. If you believe that then you really missed the point. Sticking to a consistent exercise program doesn't take willpower, it's just a matter of discipline.