Last I checked, Google isn't volunteering to manage all aspects of Android OS updates for the device vendors (as MS does for Windows), so I don't think the reversal is valid.

Google would get nothing but more work and responsibility out of such an arrangement.

Yes, it would be better for security and end users, but who cares about them? Google is in it for the ad revenue, and the HW vendors are in it to sell units, not have old models with new software compete against their new hardware.