Another issue with startups is pivots. Years ago I went all in with my company on a calculator startup, then they pivoted to an AI-focused solution that was so far from their original value prop that they became useless. Left a gap for our customers and that company doesn't seem to be doing well present day.
Yeah but if that doesn't pay the bills, can't fault them.
I agree with the general sentiment but not everyone is there thinking about multi-milion exit strategies, not everyone is buddy with people in SV or YC to even dream of that. Some people really want to solve a problem and make a living out of it, sometimes that's due to the idea, sometimes to the "customers" and sometimes something else.
Stick to what your customers want!