If Apple and especially Google really wanted to support PWAs, they'd add first-class support for them on their app stores, but they don't really want to do that, as it would weaken the walls around their garden.
GMail is bloody awful. I can hardly stand using it. Been using Thunderbird for a while now and have not many complaints.
The whole "IMAP" purist thing is unnecessary; there are plenty who prefer not using the GMail interface and have no idea what IMAP is.
Telemetry, activity tracking, etc.
NeoMutt doesn't send everything I do to a persistent log accessible to data broker parasites and NSA functionaries.
Not being turned into cattle watched over by an enormous Panopticon is a pretty major Killer App feature.
I like that it has critical features like a sane approach to contact lists and “sweep”. I also like that I can send a message with priority - a feature mysteriously still missing from gmail.
https://blog.pwabuilder.com/posts/publish-your-pwa-to-the-io...
It is Apple that has had issues with PWA support.
> While WebKit is making progress on PWA support, at the time of this writing, PWAs remain a second-class citizen on iOS. The iOS App Store’s support for PWAs is non-existent, requiring a web view-based solution like PWABuilder’s.
> Additionally, because iOS doesn’t allow 3rd party browser engines, your PWA is limited to WebKit’s PWA capabilities, which are currently lagging behind other browser engines.