It's pretty well explained here what Google is trying to do: https://www.xda-developers.com/android-project-mainline-modu...
That being said, Apple is atm way better in providing longterm software updates, but that doesn't mean Google isnt doing a lot of work there also.
Next to that, there is already a lot of apps that are updated through the Play Store instead of an OS update. Mail, Dialer, Android Auto, Photos, Camera, Keyboard, Contacts, Clock, Play services, ...