Because google exerts centralizing control over things. Where i live here in the US if you are not on the play store you may as well not exist. I am led to understand that in much of the eastern world such as china having multiple app stores and such is quite common. I personally choose not to use services from these large companies firstly to limit their abuse of my data, and secondly because most of these companies are american and must bow the knee to the american governmyth to continue to exist. The internet was made to not have a central point of failure, yet what would happen if Google, AWS, and Microsoft all just vanished? Complete chaos would happen over much of the internet and the largest impact would be to western companies.