Why don't companies just get ahead of apple here, decamp from the app store, and heavily advertise a web app instead? Most of these apps need online connectivity anyway, so having a native app isn't all that useful.
The web has played out, and I'm pretty sure most people use it for news, recipes, and Wikipedia. Everything else is done through apps. You don't see a lot of young people talking about websites. Websites are seen as something for old people, and the App Store is the easiest way to access services and social media, which is how Apple has these companies in a bind. If going to The Google or typing in a URL was as easy or easier for the average person, Apple would have lowered the cut they take a long time ago.
You can't run any sort of background code (webworkers etc). You can't have a split-view for a progressive web-app on iPad. You can't have notifications.
The lack of notifications is a big one, and one of the things that makes such apps mostly non-starters.
Coinbase's wallet app is entirely different and largely unrelated: it is a program that manages a private key on your phone so you can directly access your funds and make transactions on the underlying decentralized infrastructure. If Coinbase goes out of business their wallet app would still function and no one has access to your money except you, using this key.