A lot of poker game tournaments have been announced on this board over time, and am I kind of wondering what makes poker games so inclined to the tournament and we don't see such competitions being announced for other games?
There are competitions for other games here that are being held by different casinos. You can find them in Games and Round board. Some are free to enter (usually when the game is about prediction).
But if you're referring to games that aren't initiated by casinos except poker tournaments, it is because no one initiated it.
It is very difficult to imitate poker, particularly the most known version of texas hold'em. There is a whole culture built on this game - should I say sport - that comes back from a long time. Some say it begun in the very old China while other claim that the version that is closer to current is "poqe" played in France in the XVII century. However, it was in the US when it got to where it is today.