Considering the potential size of pages and that this would mean the browser would have to keep around all of the unmodified source for all of those, I think it

Considering the potential size of pages and that this would mean the browser would have to keep around all of the unmodified source for all of those, I think it's a decently justified position. I will say that it would be nice if there was a way for them to recognize when the devtools are open and use that as a signal to keep around the source of the current page. But otherwise it would certainly cause significant memory bloat for each tab open.