The BDFL model, as it's called, is what allows large projects to continue to have focused vision rather than devolving into design-by-committee. The kernel is actually already well beyond pure BDFL, but my point is having a single point of overall leadership can be a huge boon for the organization of large and complex projects. FOSS philosophy has literally nothing to do with management structure; it's entirely about the rights of the end user.

BDFL is not without its own risks. WordPress is a good counterexample these days. But, when someone originates a project and sticks around to steer it, it would be silly to reject their proven successful leadership for such a vague reason as you have presented.

When things do go sideways, people are free to fork the project. That is what FOSS is.