The question is more: why are people moving away from Fedora, when you look at the stats: https://fedoraproject.org/wiki/Statistics. Fedora 14 was way more used than any other later version.
I think this is related to the brokenness of the system: they pushed early a lot of the debatable technologies (*Kit, NM, systemd) that were not really ready at the time (this is a choice that can make sense) and they argued that the lack of polish was OK for developers, and moved on without "finishing" them. I kind of disagree on this latter point, and this is sometimes way too frustrating (I think the Arch way is more suited on this). And as this is not a rolling release, you need to wait a long time to get the fixes.
Their approach to multimedia, codecs and patents is also one of the more ridiculous of the Linux distributions. And that is pushing also a lot of users out of Fedora, IMHO.
As a long-time Fedora developer (and a member of FESCo during the switch over to systemd), I take offense at the idea that we claimed a lack of polish was okay. Far from it; we've spent a lot of time and effort in finishing up all of the tools you just described. I gather from your statements here that you haven't actually run Fedora in the recent past.
Did some of these things land before they were absolutely perfect? Of course. Someone has to be the first to deliver something. You can never figure out what your software is lacking until someone is using it. Fedora takes risks. As we've seen time and time again, once Fedora proves that something works (and has made the effort to polish it up), the other distributions generally pick them up and run with them. NetworkManager, systemd, SSSD, etc... all of these came to Fedora first, were improved upon there and then were adopted widely.
I keep having to remind people: Fedora does have a rolling release. It's called Rawhide and you can move any currently-supported Fedora system to it by running 'fedup --network rawhide'. This will always carry all of the packages that will become the next version of Fedora. It's fairly stable these days (not like its early history, where only the exceptionally brave would dare install it).
Lastly, our approach to codecs and proprietary device drivers is entirely because our hands are tied by legal obligations that other distributions don't have to deal with. (Canonical incorporated in a tax-haven country specifically to avoid this problem; many other distributions simply don't have an entity involved with sufficient money to be worth suing). We know it's an issue. It's one of the reasons Red Hat, Inc. is lobbying so heavily for patent reform in the United States. There are mechanisms out there for getting these tools (such as third-party repositories maintained by our non-US community), but if we tried to ship them in Fedora, we'd immediately be sued into nonexistence. So we have to choose the bad option instead of the catastrophic one.
As a perl developer, have some feedback on why i stopped using Fedora five years ago, fleeing to anything remotely more sane:
You guys actually thought it was a good idea to include Perl, but make the unilateral decision to cut out pieces of the Perl core just so the damn thing can fit on a cd-rom, forcing Perl developers in bad corporate environments to deploy Perl core libraries manually.
Not that you're alone in that, but you and your ilk will always have my ire and negative feedback to execs on that until you learn to behave and make amends.
I think this is related to the brokenness of the system: they pushed early a lot of the debatable technologies (*Kit, NM, systemd) that were not really ready at the time (this is a choice that can make sense) and they argued that the lack of polish was OK for developers, and moved on without "finishing" them. I kind of disagree on this latter point, and this is sometimes way too frustrating (I think the Arch way is more suited on this). And as this is not a rolling release, you need to wait a long time to get the fixes.
Their approach to multimedia, codecs and patents is also one of the more ridiculous of the Linux distributions. And that is pushing also a lot of users out of Fedora, IMHO.