Wouldn't this make users pay for every possible feature they could ever use on a given site? For instance, in Google Maps I might use Street View 1% of the time, and the script for it is pretty bulky. In your ideal world, would I have to preload the Street View handling scripts whenever I loaded up Google Maps at all?
If you’re asking if it would incentivize us to be more careful when introducing additional interactive functionality on a page, and how that functionality impacted performance and page speed, I expect it would.
Thinking about how the web was designed today, isn’t necessarily good when considering how it could work best tomorrow.