Anyone beliveing that project Treble will change anything should listen to the ADB Podcast about it.
http://androidbackstage.blogspot.de/2017/08/episode-75-proje...
Key points:
1 - Google will keep on allowing OEMs to customize Android
2 - OEMs will keep being responsible for delivering updates
3 - OEMs are advised to push fixes upstream and provide updates
Given that they are just advised, and not required to act accordingly, do you want to bet how many will provide Treble updates instead of selling new handsets?