This is not necessarily true. Wrong monetization can be the killing blow. Market can change and your business model which used to work can suddenly fall apart. A recent example for business model change is Tailwind where traffic to their open-source docs plummeted and suddenly not enough people are upgrading to their commercial licenses.
Startups die for a variety of reasons, even if products are popular and loved.
Tailwind was (is?) also selling "lifetime" licenses, which means eventually their sales would collapse anyway, once they have sold a license to most interested customers. They were always going to need to pivot at some point. regardless of traffic to their docs.
True enough, though I think Tailwind suffered something of a black swan event of having lifetime pricing plus AI coding assistants hitting an inflection point that immediately and thoroughly decimated the value prop of their core monetized product.