I read that as less about "building on someone else's platform" (though that's still a risk they're taking) and more a youtube / media content producer version of "perfect software doesn't pay the bills, shipping software does". I've known plenty of good developers that if they didn't have hard deadlines and people reminding them about what the real goal of the company is, would spend 6 months developing a perfect, provably correct PDF to JSON converter for reading any possible design of tables in all PDFs. Missing the fact that they only need to parse the tables in the CSV files that the vendors are sending us so we can invoice the customers.

That quote reads like its reminding people that youtube and a youtube production company job is not where you go to make art house silent films.