If they were to sell the HL franchise they risk losing a lot of customer support overnight. They would no longer be game devs, whose blunders can be excused because of their amazing games, they are money grabbers willing to whore out their franchises for short term cash grabs. The risk to the Steam platform just doesn't seem worth it.
If they were to sell it MS would be one of the worst destinations for it. If I were in their shoes I would likely explore having a smaller studio build it. A sale to MS could only be viewed as financially motivated and the quality of the game produced is almost certain to suffer.
However if I were them I would keep it as an ace up the sleeve to bring the masses to a new H/W platform Valve bring out. Such a release could seal the platform that wins its generation of consoles.
So the next generation of consoles or so they release a steam machine with VR tools and their 'next gen' games.
So still PC, but packagable for console users
I think it mostly boils down to Valve being a privately held company that is not under pressure to meet arbitrary quarterly financial targets. The article is quite clear that Gabe Newell gutted HL a few months before the original release date rather than deliver a game that wasn't quite "there" yet.
Additionally, if Valve have maintained their notoriously flat structure, HL3 will need to acquire critical mass /buy-in within Valve before it can make it out the door.
> Even if Valve decides against ever doing HL3, could they afford not to sell the franchise?
Yes, as long as Steam remains a money printing machine, they will not be desperate.
Wait, why is that? Isn't this 2016 where any game or movie that is even a little successful, must inevitably have successors?
How could valve motivate not making a game that would sell like hotcakes no matter how terrible it is? Sure, it would have enormous expectations, but that's true of all movie sequels (yet most suck). Is the value of Valve currently based on a game they'll never make, because it' can't live up to expectations? That would be an odd situation!
Even if Valve decides against ever doing HL3, could they afford not to sell the franchise? It must be worth a TON to e.g. Microsoft who could use the title it to push xboxes or VR headsets or whatever.