Heh, I remember thinking the same thing about Capcom when Phoenix Wright first came out in 2005 or so. At least they're still at it.
(I wouldn't say they're single-handedly keeping the genre alive, but they have managed to make adventure games cool to a not-typical adventure game audience, in a way that most other publishers seem unable to. What struck when Phoenix Wright first came out was how many non adventure gamers were playing it and saying, "Wow, this is great, there's never been another game like this, etc." I mean, on more than one occasion, I had Gamestop clerks telling me about this great new kind of game I just had to try out. That had never happened to me before...)
