But I don't see it as fragmentation, but as competition. The better idea tends to prevail, and it's nice that the environment allowed alternatives to even try :)
hell, systemd itself happened as a esult of this environment :)
Experimentation is OK. DNF started as a yum fork, with a different solver algorithm. IMHO yum should've just adopted the algorithm, but Fedora/CentOS ended up switching. That's mostly fine (people had to update docs, retrain their muscle memory).
The level of "competition" we see in package managers, desktop environments, initrd builders (!), resolv.conf managers (!!!), is just wasted effort. There's no "pick the winner", it's "everyone is a loser".