What we've been doing for the past several decades is having the government borrow a ton and spend it on entitlements and the military budget.
Yet... neither are the root of the problem. Compounding factors...
...but the economy would have run against a wall either way. The governments involvement only really matters as in that it "maybe" happened "a little bit sooner than later".
What is certain however is that if there was no government regulation (or government) at all (i.e. what all the free market idiots are lobbying for)... it would have happened a LOT sooner.

It's hilarious that that fact still hasn't sunken in and people are often still repeating "lower taxes" "less government" like a mantra... well guess what? .... That didn't work the last decades, it won't work now. It certainly won't fix the underlaying issue that causes the whole economy to finally go haywire. The most hilarious thing is that some people may now accuse me for wanting "higher taxes and more government" as if it was only these 2 alternatives with *nothing* else that the government can do that matters.
The government at this point (by choice or lack of alternatives, who knows) is a somewhat impotent bystander, throwing money at a forest fire when asked to because it can't imagine what else to do and doesn't wanna get "caught appearing" not to do anything.
What the US really faces is a systemic crisis caused through pervasive business practices that were never viable in the longterm.