1. We gravitated towards a new css framework following some initial work with existing web apps that were responsively designed. While some well-designed responsive web apps might make it to a level where they genuinely feel like mobile apps, we figured most websites reduce responsiveness to the idea of just shrinking the desktop UI to fit the handheld format. That isn't enough and those are the folks who are going to need the new CSS framework.
And yes, one would have to recode their website or plan a separate stylesheet for app-in-webview using parts of Toucaan.
2. I agree that Apple has fought the web and the web standards for a long time, but they do not reject wrapped web apps that meet their app store guidelines. Besides, it doesn't have to be a pure web-view if that is what it takes to get your app through the door. I'd say much of this depends on case to case basis, and it is in the interest of every business owner to go in with the cheapest web-view option first.
A Red Goose app is a web-view, but it also a starter app in Swift and Kotlin. So you can choose to get into native development should there be a need to. And get the best of both the worlds. I don't know, the likelihood of Apple booting the entire web-view based ecosystem from the app stores is fairly low. Even their Safari is a web-view based app. :-)