OrbitGuy
Loving YTtalk
I doubt they would actually change this permanently. The twitter post says this was just to help improve the auto generated ones for those who do use them, not to replace the custom ones. Big players on this platform want professional looking thumbnails, and auto generated is like a decade outdated. I know people don't have a lot of trust in YouTube recently but I think they're smarter than to actually take out custom thumbnails, that's just a straight downgrade for producing professional looking content.