I think startups die because they are pressured to spend a dollar or more for every dollar that comes in.
Bootstrapped businesses are forced to retain cash for a rainy day. It is anti-fragile vs the fragile nature of a negative/break even cash flow business that depends on a steady stream of investors who introduce other investors who introduce other investors. It's built on ego and not on fundamentals and humans are fallible.
These days you can just get a loan from a bank if you have a high enough MRR to cover the interest rate. No equity, no control traded for a 3rd party who's sole interest is ROI.
I've personally seen bootstrapped businesses that had healthy MRRs rapidly transform into a race to zero or negative cashflow. When I questioned the robustness, I was told by a software engineer angrily I didn't know what I was talking about and that perhaps my economic degree wasn't any use lol. I don't think he's equity is worth anything now but the whole scenario reminded me of the Horse in Animal Farm.
The fake it till you get bought out by a giant is a lottery. Don't trade your life for one.