> and more to do with the web becoming the default application platform.

I dont even see any trend to suggest that is the case. Even if you count Electron as being one. Most Apps are not web based, and dont ever intends to be.

>So developers expect native OS level API access from browsers.

Exactly. It was certain group of developers that want the Web to be the default Application platform, starting with Mozilla's Firefox OS and later Chrome OS.

I think we need to differentiate a Web Page Engine and a Web App Engine. Although I would agree that even a Web Page Engine today is far too complex.