"Upstream" for Ubuntu is more like Debian, which is the basis for MANY distros (much like Red Hat - founded around the same time as Debian - and the .rpm ecosystem is a significant core component of many systems including current versions of SuSE, etc.). Ubuntu has traditionally been a slightly more newbie-friendly / commercial-friendly version of Debian. I don't think many of the changes you're describing were really trying to defy Fedora, especially not the choice to use .deb over .rpm.
That said, I did use Fedora for a while when Ubuntu started messing with Gnome a lot and I found it very refreshing, easy and reliable. It's a great distro, but the relationship between the two is absolutely not "upstream" and "downstream".