Originally Posted by Trunks0
They kinda sorta have. Starting with phones launching on Androud 8.0, they have to implement a feature of 8 called Treble. Allowing the OS to stay nice and updated.
Should be noted, that the Essential Phone PH-1 will be implementing it for Android 8.0.
Here's a good read on Treble and what Google wants to accomplish. There will still be some issues, but this is a great start.