They'd be a lot more of them if iPhone supported the technology better.
I say that as someone who's pitched PWAs to companies, but since many of the managers and owners seem to be in on the Apple ecosystem, demos often aren't that impressive. Having to answer "kinda" to can they do x questions doesn't go down well.
I'm using the Kbin pwa on an iPhone and it works much better than I expected it to, I don't know they must have better support now. I think the functionality should be more than enough for many companies and much cheaper than a custom native app
I'm confused about where development of PWAs is even going. Between the two and a half big browsers, only Chrome/Android seem to be adopting them seriously, I've seen people complain about Firefox not doing a great job, and I have no idea about Safari (but on iOS, I can see why Apple would have a huge incentive to prevent people from bypassing their Developer account fees)...
I'm right now browsing the fediverse and writing this from the Kbin pwa. It seems to work quite well, with some quirks that I guess could be polished, but overall better experience than most installed apps that should be a website instead
They're still a thing. If your work uses Google Chat instead of Slack / Teams the only way to install an app version is as a PWA. A company I recently worked for just got most people to use the Outlook PWA instead of the traditional desktop client, and I frequently use Spotify and Soundcloud's PWAs. One of the more popular backend API testing apps is hopscotch which is entirely a PWA, and this was also written on Voyager for Lemmy.