I generally like Valve, but fuck them for dropping the ball.
HL3 still being a pipe dream is an absolute business failure on their part.
I understand your frustration. I want HL3 too. But Valve's absolute business failure? I think NOT devoting resources to HL3 was the right decision from company's perspective.
Valve is rich as ever in epic proportions thanks to Steam. Also Valve has wisely adopted microtransaction model of Dota 2- their biggest cash cow.
Of course L4D3 will come out, because it's a casual game. L4D2 was not even a sequel. Same engine, minor differences, it should be called an upgrade. By that precedence, L4D3 will be a 'pressure-free' product of a sequel that'll make $$$.
Half Life is different. Every HL revolutionalized FPS gaming. I don't need to state how HL1 changed the FPS industry. Same for HL2- I still remember vividly how floored I was at gravity gun and true physics interaction in 3D environment.
So, HL3 will be held to same expectation for making a ground-breaking transformation of a game. And that's a near impossible, tall order today.
I'm not even mad if HL3 never comes out. Hell, people who loved HL1 & 2 are fathers in 30-50s now. We are no longer the target mass audience.