Disclaimer : I'm nobody important, but I do have an opinion
If scala team were to disavow sbt, that'd be the single best thing they could possibly do for the ecosystem.
I used to write a lot of scala, and working with sbt was enough to eventually get under my skin.
I really like some of the OOP aspects of scala, the left-to-right style of thinking matches how my brain works. Scala having a lot to offer can distract new learners, especially with just how overwhelming all the different features can seem for someone not coming from both sides. I had ocaml and ruby under my belt when I found scala, so it was an easier curve, but lots of guys struggle with it. I don't mind showing them, and of course I learn a lot from guys with different experiences and different backgrounds, but that's sometimes a complain I hear, also.
It's a language that doesn't compare very well. What is scala like? We don't know, there's only one language like it, it's a departure from many different paradigms.
I'm back to writing ocaml, all said and done. I enjoyed my time with scala, and interacting with my guys on the other side of the office still doing scala is always enjoyable. Smart guys! I'm not academic enough to grasp some of the new DOT stuff, but they are excited about it.
Anyways, I gave up hope a while back on scala getting rid of sbt. There are other build tools that exist, cbt, mill, maybe more, but without the blessing from lightbend or whatever they call themselves this week, it's not feasible, or responsible to deliver a solution to a client with an unofficial build setup. Of course, after five years of doing sbt I decided it's not ok to deliver sbt either.
Someday! Maybe?!