Obviously successful startups are lucky. I think the idea of releasing quickly/efficiently is to test the market to see if a larger, more complex product is desired (IOW can you get lucky?). In the example provided, a beta release of one level of Ryzom could have saved years of dev time if it was not well received.
They did a beta release. People loved it. Then they did a massive change to XP distribution shortly before release that forced people to run in single squads, because experience couldn't be shared among multiple squads cooperating anymore. People hated it. Nevrax didn't give a fuck and released anyhow.