I think it depends a lot on what you mean by "compete". I'm a heavy Twitter user. I now only use its PWA on Android and it's fine. I wouldn't call it perfect, but it's certainly very usable, and I suspect most non-experts would have a hard time telling that it's not a native app.

Especially for MVPs, I think they're competitive for a wide range of uses. The UX may not be as polished, but that can be more than made up for by instant availability, instant updates, lower dev costs, and faster release cycles. The ability of a new company to learn is limited by release cycle time, and I think fast, low-cost learning is a huge advantage to startups.