Why can't I collect on it?

Betting on systemic collapse of society has a challenge at the winnings collection point.

"Here's your trillion dollars. Go buy a slice of bread. Ooops… half slice. Well, quarter."

huh? he can just short the companies he's so concerned about

What good is that if the entire socioeconomic system collapses?

Yeah, except the money you made is now worthless.

https://en.wikipedia.org/wiki/Zimbabwean_one_hundred_trillio...

That’s not what would happen if he shorts it. It would be like 2008 recession where people did make money.

In fact shorting is the moral thing to do now because it nudges towards bankruptcy faster

Unfortunately the market can stay irrational longer than you* can stay solvent.

* For most definitions of "you"