Linux does not have fragmentation at all. I'd like to see you prove that one. You can write your software and only focus on one distro. Valve for example focusses on Ubuntu but I have Steam running on Arch Linux with no issues.
What do you call Wayland, & Mir (and I suppose X) ?
You have lots of people on each of these, instead of pooling together to make a standard.
Without a standard, then OEMs are left with picking one over the other.
That, is fragmentation.
The beauty about Linux is that there are many kickass distros. If we only had one and it went south what would happen. See what Microsoft did with Windows 8 for reference.
If they all follow some kind of standard, then it would be easier to port whatever from one distro to another.
This isn't always possible right now.
The reason Debian doesn't recognise those things is because it does not include non-free (closed source) drivers by default.
Nice try though. You can now install Ubuntu and get those things installed if you want to. The TV tuner card may be a hassle.
Yeah, I know this, but, even with enabling non-free, it still doesn't work on hardware that has no drivers.
What you say is a 'hassle' turns into impossible.
http://www.linuxtv.org/wiki/index.php/ATSC_PCI_Cards#Currently_Unsupported_ATSC_PCI_cards
While I do like linux for some tasks, it just isn't getting the support from OEMs to get drivers it needs to compete fully with windows.
There is no distro (well, Ubuntu is trying) that all the OEMs can get behind and offer full support for their hardware.
Lots of people will not use the binary blobs available, for whatever reason.
While they make some good efforts with the OS video drivers, they still lag behind the binary blobs and that just isn't going to change anytime soon.
QUick example, windows drivers have openGL 4.3 support, the OS ones barely have 3.
Thus, we come to what the OP's title says, '...Linux still isn't ready for prime-time.' and, that is true.