IE was "solid" as long as you only worked inside it's constraints.
iOS/Safari is worse than IE because it's exclusive. At least with IE/Windows you could install something else.
OS lock-in and slow adoption of new web features is perhaps lame but Safari doesn't have anything even approaching it's own box model, or `-ms-filter` equivalent, or quirks mode... the list approaches infinity.
Also, "install something else?" Do you know what the browser landscape looked like back then? IE had >80% dominance for years, and your other option was Netscape, which lacked huge swaths of custom features in IE.
The expectations and businesses relying on browser functionality back then is minimal compared to today which amplifies the core issues at hand.
Try building an PWA with offline capabilities (trivial in modern browsers) that's your core of your business, and you will see what I see. Apple is _trying_ to strangle non-app store apps. Where IE was just a dumb lumbering problem by comparison.
I have, for one of the world's largest companies. You're missing the forest for the trees if you feel PWAs are this much of a linchpin to the broader conversation.
So if your PWA works on iOS/Safari, great for you, but it doesn't mean everyone's does.