Absolutely not. There are plenty of other innovative titles on the market. I like that there's at least one series that remains constant for me to pick up a new iteration of.
Besides, they do a good job of tweaking the Pokemon formula each game to improve it. Many might disagree, and say that they don't change enough, but considering that almost every new title brings a slew of complaints from the meta about the battle mechanics being different and now having to "retrain" a lot of Pokemon, I'd say that they are, in fact, changing the games well enough each time. To ask Gamefreak to drastically change Pokemon would be similar to asking Riot to drastically change League of Legends; it's already got a firmly established competitive meta, so any changes to the series really should be done in smaller doses. And even those changes (such as the retweaking stats of a lot of the items that happened a little while ago in League) seem pretty big to those devoted to the game.
Continuing a point from my previous post, the only reason that they would *need* to drastically change Pokemon, or stop making it, would be if it were dying. But as long as fans remain loyal to the series, then it's good for the series to remain loyal to its fans.