Because GPL people don't play well with others. It's not enough to make a good tool, you have to force people to use it. So, we get crap like systemd, unity and wayland being made as a way of wanking off.

Personally, I'll be going back to FreeBSD as I've gotten rather tired of the bullshit.

EDIT: And let's not forget pulseaudio that seems to be deliberately incompatible with the other ones.

1.Wayland is under the x11 license (and Xorg REALLY needs to die)

2. OpenRC works now, DMD is being worked on and even SysV is still an option for init

3.Unity is only one out of a dozen of desktops to choose from (LXQT/PLASMA5 ftw).

4. You can still just use pure ALSA...

Oh, I wrote it that way at first but I reworded my post and forgot to add that paragraph back in.
I can't see a reason to want to use Unity either...

You don't know jack about Linux, do you? xD
Yep. They only use LTS versions lately though.
Think Linux as the very base. Then upon that you use different software to get shit done. That would be Debian.
And then, upon that, you can install software on your own. Some distros, such as mint and ubuntu, take a base (Debian on this case) and add packages. Even if some are distro-specific (mint updater for example), most software can be installed without diifficulty. So, with enough willpower, you could download a netinstall Debian iso and, without taking on account the packages' versions, build from console everything you need, just installing them one by one (just like if you had a massive "filehippo" or similar app).

But, as I said, the versions and custom packages are an incovenience sometimes for some people.

But yes, you can stick with base Ubuntu, purge Unity and install whatever desktop and whatever packages you desire and makes little to no difference to a distro using the same repositories.

Long term support (LTS) versions are easier to support. And their binaries will most likely work on new releases too. They just won't be officialy supported. That means you would have to solve the incompatibilites and problems yourself. The users of other distros are already doing this anyway so there's likely a lot of info on that.

1. Xorg has far more capabilities than what most people use as it is. I don't even scratch the surface of what it's capable of normally. Yes, there are some issues with it, but I fail to see why it needs to die rather than be fixed. I remember people saying the same thing about XFree86, and that was mostly a matter of actually fixing things.

2. I have no idea there, but it seems like systemd is getting harder to avoid as it expands and displacing other things. I'm looking further down the road on that one. It's a concern I have about the direction, not the present location.

3. That's true, but I'm still pissed off at Ubuntu for dropping that crap into the release without bothering to do any QA.

4. Not really, Pulseaudio doesn't play well with other options, if you've got software that's using it, it tends not to work well with ALSA. Or at least that's been my experience with it.

I got my LTS versions mixed up. But it is official that GOG supports each Ubuntu LTS that comes out?

Ubuntu and Mint, yes, although Mint only follows LTS releases starting with 17 (based on Ubuntu 14.04). See this post for official announcement.

But I have also seen evidence here where GOG staff kindly offered a helping hand regarding STS versions of said operating systems.

But with the new Linux installers recently out, number of distros their games work out-of-the-box on is bigger than ever, although no official support for them has been advertised.

Yes, see here (the second answer under "General Questions"):

http://www.gog.com/support/support_view/bgeneral_troubleshooting_faq_linux_ubuntu_mint_gamesb Edit: Oh, v3 answered it already, sorry for the double post.