I'm not well versed with PWA topics but as long as Apple doesn't curve around this, we can't expect a wide adaptation of it. Don't get me wrong, PWA can be the future but not without the whole Apple ecosystem missing.
Learn to ignore garbage companies like Apple if you don't want to be treated like garbage by them. They don't matter. If Safari does not support the latest and greatest, Safari is garbage and show this message on your website with big bold letters.