This has been considered and rejected as inferior to the current approach. The Android browser used this and it was rewritten to get rid of it.
Let's focus on doing things that improve the user experience rather than blindly copying features from other browsers without considering if they make sense.
Moreover, it has absolutely nothing to do with the question asked.
Didn't they ditch Electrolysis because of issues with many nsplugins? I am not aware of other reasons it was shitcanned.