They sold Counterstrike as a retail release when it was still a mod. The donation stuff is a sure way to make sure almost no one ever even considers paying.
Eh, yes. But at this point it had a gigantic following and was no longer considered to be in "beta". That said, if you had HL1, you could still download it for free, whereas if you did not and you just wanted CS, you could buy CS. There is a distinct difference.
As far as donations, there is no way you can assume that. Sure, a vast majority won't pay, but I'm sure there are those out there who are generous enough to throw a dollar or two out there to support the modder. Shit, it works for server admins.
Edit: Donations also work for people who contribute nothing and just stream themselves playing games. Some do very well, so I would venture a guess and say a modder putting out quality content could gather a few bucks.
That's not really comparable, they sold a version of Counterstrike that did not require a copy of Half-Life to play, so at that point it wasn't really a "mod" any more.
As far as donations, there is no way you can assume that. Sure, a vast majority won't pay, but I'm sure there are those out there who are generous enough to throw a dollar or two out there to support the modder. Shit, it works for server admins.
Edit: Donations also work for people who contribute nothing and just stream themselves playing games. Some do very well, so I would venture a guess and say a modder putting out quality content could gather a few bucks.