That's one strategy. Plenty of liquidity means (literally) that you're rich. So your strategy is 1) be rich 2) buy undervalued assets post-crash.

Your strategy is okay. For those set of assumptions I suggest you remove the second step, which might significantly reduce your being rich. So, 1) Keep plenty of liquidty. Buy nothing pre- or post-crash.

This has a very high probability of keeping you rich.

Now on to us mere mortals. In bubble times did you know you can actually start a company with like a few hundred dollars, start delivering product and getting users, and get investment to accelerate the process?

That way, you can build a company with cheap capital even if you're not already "plenty liquid", as you might put it.

Exactly. People seem to think that you make money by riding a bubble to the top, then jumping off when the timing is right at its peak. Turns out that is a great way to lose money (nobody jumps off fast enough). The real money is made cleaning up after a disaster.