Assuming that's true, it would be interesting to know what the alternative funding sources are, and whether they're appropriate or accessible to non-wealthy first timers building product companies.
VC is ostensibly generally accessible. Even accelerators like YC are VC-track.
the untold secret of bootstrapping to date is that is has often been done from positions of privilege: family money, savings from a very high paying career, spouse's salary, inheritance. Very hard to make broad generalizations since the companies are often privately held and under the radar (so no statistically significant data) but my experience is that the case far more often than you would think.
On the other side, I see many many founders essentially twist their business plan into something VCs want to see because accelerators/VCs are the only source of capital for early stage tech companies.
VC is ostensibly generally accessible. Even accelerators like YC are VC-track.