1. Massive hype suspended the critical faculties of many gamers (maybe fueled by Murray's geeky and somewhat confused countenance) and the game saw substantial pre-orders.

2. Sandbox, infinite exploration nature of the game meant massive numbers were playing after launch despite disappointment and frustration in the game. It does offer a unique experience.

3. After a period of keeping their heads down as an organization -- probably partially to try to avoid a lawsuit -- they started rolling out free updates that pushed the game forward enough to maintain interest.

The game was hugely successful, even by AAA standards. Combined with a tiny team means they could likely put out free updates for another decade.

I have a feeling they're playing the long game. Once they've unequivocally won people over with updates they'll likely use their war chest and momentum to roll out another insanely ambitious title, though they might stick to a PC release so they can manage expectations better.