I'm afraid you are naive.

This is not a lone idiot in an otherwise sane industry. People like this can thrive and remain blissfully ignorant because the entire ecosystem around them is incompetent, from senior executive to junior trainee.

In our industry, entire companies operate in complete isolation, basing their practices on the knowledge of their most "senior" engineer who was there at the beginning, however clueless that engineer might be. Companies like this can continue to operate successfully for many years, moving from one client to the other, and you will find them in any niche of the software industry, including startups.