Even at the start they were unusual as they were funded by Microsoft millionaires, and presumably had little pressure to release before "when it's done", and HL

Even at the start they were unusual as they were funded by Microsoft millionaires, and presumably had little pressure to release before "when it's done", and HL1 being a huge hit started the ball rolling allowing them to acquire the team fortress and counter-strike mod teams, picking up even more momentum.