My company is currently porting a critical app to React, yet I feel similar to you on most of your points. The app in question is currently using Angular 9, so a fairly similar beast. But React, by comparison, is worse in most ways IMO. The ugly syntax forced by JSX, the combination of template and logic together in 1 file, the odd forcing of certain unintuitive abstraction patterns while also claiming to be "not opinionated" about other crucial aspects of how an app works, and I certainly agree it is not special.
However, your argument starts to erode for me when you claim you'd rather spend a few months to build your own moat. You're not just choosing to incur that cost once when you build it. You're incurring a multi-month charge of developer cost that doesn't result in anything being produced for every dev you add to the team, as they have to learn the ins and outs of your proprietary abstraction without the aid of any documentation (assuming) or community to help when they get stuck. This also means a large part of your time is now spent reactively answering pings for special case questions and "what does this opaque error mean" and "how come this thing doesn't work when I do that thing"? And good luck hiring devs who are excited to work on your special creation, not to mention how you have to adapt your hiring process to determine who will be likely to succeed in such an environment. That sounds like a lot of stress to place on a fledgling company trying to grow at a crucial stage and could certainly be a contributing factor in your post-mortem when things don't work out.
By contrast, by advertising for React vs Angular devs we can expand our candidate pool 5-10x and anticipate reduced ramp up time and increased velocity out of the gate. And since hiring and growing my team is one of the most expensive and difficult things I'm grappling with, that's what I'm optimizing for. In the battle between pragmatism and idealism, pragmatism wins the day once again.
However, your argument starts to erode for me when you claim you'd rather spend a few months to build your own moat. You're not just choosing to incur that cost once when you build it. You're incurring a multi-month charge of developer cost that doesn't result in anything being produced for every dev you add to the team, as they have to learn the ins and outs of your proprietary abstraction without the aid of any documentation (assuming) or community to help when they get stuck. This also means a large part of your time is now spent reactively answering pings for special case questions and "what does this opaque error mean" and "how come this thing doesn't work when I do that thing"? And good luck hiring devs who are excited to work on your special creation, not to mention how you have to adapt your hiring process to determine who will be likely to succeed in such an environment. That sounds like a lot of stress to place on a fledgling company trying to grow at a crucial stage and could certainly be a contributing factor in your post-mortem when things don't work out.
By contrast, by advertising for React vs Angular devs we can expand our candidate pool 5-10x and anticipate reduced ramp up time and increased velocity out of the gate. And since hiring and growing my team is one of the most expensive and difficult things I'm grappling with, that's what I'm optimizing for. In the battle between pragmatism and idealism, pragmatism wins the day once again.