Interest in general has been going away from Pok?mon Go on a pretty massive scale so it doesn't really surprise me.
Seems to have been hit by what I'd call "The Ruzzle Effect"... I can completely understand that they wouldn't want to put the man hours into something that's fading out of relevance almost as quickly as it set the world on fire.
For those hurt though... we're Windows Phone peoples... we're used to getting the less-popular alternative. Want that style gameplay? Check out
Monster Buster: World Invasion... same gameplay concept, it actually has a better battle system, they actually have a way to get some action when in situations where you have to be in one place... and it's actually been bringing that Pok?mon Go-style GPS based monster hunting two years prior to Pok?mon Go... and if for some reason you wanna play it on PC instead of just mobile... it's universal.