The point is, on my website at least, none of the transition or prefetching was being used by most visitors. About 85% of people hit one page, stayed for a few minutes, and then left. In that case all that JS is just a waste of downloaded data. That's why I moved my site to static HTML and CSS. Slightly annoyingly ever since I did that the number of users who only read one page has dropped to about 75%, but I still see it as a benefit.