Just to be clear, I see no reason to use Snap/etc. over older packaging solutions. However I wouldn't necessarily agree that this automatically increases fragmentation. If Snap/etc. were to support Ubuntu, debian, Redhat, etc., they could provide maintainers a single target across many systems. Then the maintainer could just target that solution and be done. Of course this requires them to win that developer marketshare, but if they believe they can, then they believe they can achieve their goals without fragmenting they system.

I personally don't see the need for these systems, but I still see absolutely nothing special about packaging. No maintainer has to support these new packaging methods if they want. If some developers believe they can introduce new and improved packaging systems, I wish them luck.