You may be confusing web based apps with something else.
A web based app - an app that pretty much has all it's code inside of a webkit view - are perfectly acceptable in the App Store. They are generally frowned upon, but they will be accepted.
Would Apple ever build a system to develop web based apps? I don't think so.
TVOS specifically lacks any kind of web view, at all. TVOS being the latest "OS" from Apple, missing webkit says a lot IMO. They didn't want anyone cutting corners and just dumping code into a web view.
Swift is only 2 years old now and the syntax is much easier compared to Obj-C. It's not exactly as easy as JS, but the from what I read, it's much more forgiving then Obj-C ever was.
And there are already a ton of players in this space. React Native; Phonegap; Appcelerator; to name a few. I just came across another one today called GameSalad.
I don't think this is somewhere Apple wants to play; nor should they. Getting an app into production might be quicker with a web wrapper; but it doesn't produce nearly the same quality product.