Came to say most of this and agree 100%. I would like to add more to this. Not only stock apps are not replaceable on most devices but they might not even wor

Came to say most of this and agree 100%. I would like to add more to this. Not only stock apps are not replaceable on most devices but they might not even work as OEMs are notorious with their ROMs and don't use all of the Android hardware API in their apps instead develop their own which makes it easy for them to update. This sounds good but isn't as most good third-party apps use those drivers & APIs to make them work. That is why until M fingerprint sensor mostly worked on all apps which used Android's fingerprint API but wouldn't work on a lot of devices as OEMs used their own to integrate in the device.