> At the end of the day you are using a DRM front end (steam)
I take it you don't use Steam.
Yes, Steam is DRM, but it's the most non-intrusive DRM to have ever existed. You can play your games offline. There are no "false positive" errors when it comes to copy protection. No activation limits. I've done at least 5 system overhauls since Steam came out, and I've never had it tell me "Sorry, you can't reinstall that game!"
I mean, yeah, if you're the type to go "ALL DRM IS BAD!", then none of this will convince you. But it should be worth noting that I have NEVER heard of anybody getting blocked from downloading or playing a game they bought from Steam.
> that fragments the mod ecosystem
More like, it replaces it with an excellent platform. Have you even HEARD of Steam Workshop?
> and obfuscates the process of installing and running the software you paid for on your own computer.
This is a feature, not a bug.
Also, once you've installed a game, you don't even HAVE to run it through Steam. You can just as easily find the executable and run it directly.