Reading this article and other things, I don't see it declining so much. It was the most downloaded app worldwide in 2023 and had the largest consumer spending in 2023 ( https://techcrunch.com/2024/01/10/app-economy-recovered-in-2... ).

Yes, now that it is number one in these categories it is "mature" and its growth rate as not as fast as it was as it was climbing to these numbers. I don't see how being #1 in the world for app downloads and sales means it is "in decline".