[datashovel]

In a nutshell. It would only be a simple shell, with extremely minimal API (for user settings, etc), which could sandbox browser engines. This (a) makes "switching between browsers" a seamless experience to the end user, (b) makes the development experience much more friendly to the developer [since they're developing for their browser engine of choice].

[AnIdiotOnTheNet]

Dear god why. What is the point of using the web if I'm going to target specific browser engines only? I may as well write native apps and target specific OSs only.

If your idea were implemented, I'd expect that in 30 years someone will propose the meta-meta-browser so developers can choose the meta-browser that hosts their chosen browser engine.

[datashovel]

I don't get the impression you understood what I said.