I think they wanted to somewhat replicate what they had on macOS, where the best and most popular apps were those built by indie/boutique dev houses that cared

I think they wanted to somewhat replicate what they had on macOS, where the best and most popular apps were those built by indie/boutique dev houses that cared specifically about building great iOS apps. Lowest common denominator apps that treated iOS as a generic mobile target (and thus, ignoring platform conventions and such) were undesired. I’m not sure that ever could’ve happened given the popularity of iOS, though. Companies like Panic and Omni Group don’t have the sort of firepower it takes to compete against the sheer amount of money poured into marketing by Facebook, Google, VC-backed startups, etc.