That's just silly. No company is going to buy a game just because a few people play on a private server, and NCSoft will sell it to the players if it wants to, regardless of whether we're playing on a private server or not.
Tell that to Vircom. Their MMO game
The 4th Coming went through a similar process. The game launched in 1998 and did well for several years. People figured out enough of the backend to emulate T4C sometime in 2002. Vircom sued over it, but as is typical with such things, they couldn't kill it with the code and documentation already 'in the wild.' A couple of years later, in 2004, Vircom shut down T4C in North America (I'm not sure about Europe, but probably there too, even though another company was involved). That opened the doors for emulated servers to start popping up all over the place, so the game retained visibility
So in 2006 Dialsoft saw all those emulated servers as evidence that there was still money to be made from T4C and bought it from Vircom -- their plan being to license official servers as an alternative to the less than perfect emulated ones (fans might even have been shopping the idea around to investors, I don't know). That situation is still live today, though Dialsoft did close the doors on any
new server licenses this year.