From what I understand, Gabe/Valve almost went bust during Half Life's development. His gamble paid off when that turned into a runaway success, but he still could have lost it when he bet again on HL2 and Steam; at the time it was extremely controversial to make those a package deal. If Half Life 2 had been not quite as good as it turned out to be, it could have turned out to be a studio with a one hit wonder that burned their goodwill with some sketchy DRM sort of scheme on their second game.