Comment by programminggeek

I don't think Apple's customers are clamoring for Progressive Web App support as much as they are wanting other features.

The average customer (of which Apple has millions worldwide) wants a device that solves some basic desires like taking pictures, making phone calls, texting, email, etc.

I don't see how this feature serves enough of those customers for Apple to care more about it than something that will sell computers (in some form or another).