Yeah imagine that. They want people to work with others. So communistic!
It's amazing how people are. Valve releases L4D2 and people flip out accusing them of pushing titles out. They hold back on continuing HL until they have something great, and people whine because they don't release enough.
Meanwhile in past decade they've revolutionized how we buy games, have released around 10 games, and back-ported everything they've made to Mac and Linux.