They are completely crowd funded, and with how much they have raised (>$200 million), it would be silly for them to sign with a publisher or seek investment. In the beginning they were looking at signing investors, but they raised enough to not need that. Also, with the 2 million people who have already backed the game, they do not need to do traditional advertisements. They do have a presence at game conferences, and produce quite a bit of video about the development of the game as pretty much their only form of advertising.

They raised that money in part by saying "We're going to spend this money on game development." I don't think they could turn around and spend $50M of it on advertising without inviting lawsuits.

They also said they were going to raise that money to make a game by 2014. A few people have successfully sued to get refunds but I don't think they care much about the original terms they used when raising money.

CIG's own legal argument is that they have already shipped the game in the form of 3.0 alpha, thus the ToS was amended to forbid any refund beyond the basic cooling off period following purchase. Challeges has so far not been successful.

I really enjoy their Bugsmashers series on Youtube, where they walk through fixing code. It's great in its own right, and I'd watch it even if it wasn't about Star Citizen.

They do have a paid subscription service that pays for promo materials. I suppose it depends on how much you trust the organization to firewall different money sources.