It looks like all those pills Dr. Mario was prescribing willy-nilly have ended his career. Nintendo has announced that Dr. Mario World isn't long for this world, and so the game will be shut down on November 1st. Starting today, the title's in-game currency (Diamonds) are no longer being sold. Oddly enough, your play history will remain available after Dr. Mario World is shut down, which will be moved to an accessible web page once the servers are offline.
Above, you can read the full announcement for the upcoming closure of Dr. Mario World. As you can see, Nintendo hasn't provided a single reason for this shuttering, but my guess is the game wasn't making any money because nobody was playing it, more than likely due to the poor balancing where you'd either win easily or lose spectacularly. Yet another mobile game taken down by a developer's incompetence to balance a blatant cash-grab for fun. I suppose it's pretty difficult to hit that sweet spot where you keep players addicted without annoying them, almost as if tricking people into playing casinos disguised as games is a tough sell. But hey, at least Nintendo got to drag a fan-favorite mascot through the mud for some easy cash.
As you would expect, the ability to purchase in-game currency has already been pulled from the title, and so if you happen to have any leftover, it's probably a good idea to spend what you have before Dr. Mario World is closed on November 1st. It would seem player history will remain accessible after the shutdown, which will be moved to a website once the servers are closed.
Honestly, I can't say it's surprising to hear that Nintendo will shut down Dr. Mario World before the year is out. Even though it looked the part, it was clear there was no meat to the title with extended play. It operated more like a greedy match-3 game instead of a true Dr. Mario title. The game's advertisements are disruptive and annoying, the monetization flat out stinks, and the gameplay is balanced so poorly it's easy to see that you're being pushed to spend money. So for me, I say good riddance. There's no place for this sort of blatant greed in gaming, especially from Nintendo.