A few hours ago, there was a tweet by the Black Mesa developers with a link to some information about the state of affairs and their plans for the future of the mod. Here is the link to the post http://forums.blackmesasource.com/showthread.php?p=564005.
I haven't seen a post about this yet and just wanted to give a shout-out to those who haven't seen it.
It looks like the Steam version of Black Mesa will not be a free mod after all. I think it's perfectly legit for them to commercialize their work and they said it's mainly a way for the fans to support them although there will be some additional features for the supporters. And they're not completely discontinuing support for the free version. But that's just my personal opinion. What do you think?