They introduced a new Python like syntax, and pushed to move away from the curly based syntax.

There were other breaking changes as well.

https://docs.scala-lang.org/scala3/guides/migration/compatib...

This naturally broke all the tooling.

Then you have Metals for VSCode InteliJ plugins, while the Eclipse plugin was dropped.

InteliJ plugin is much further than Metals, however there is the conflict of interests with pushing Kotlin instead.

Meanwhile most Scala shops have pivoted to also give feature parity on modern Java, and Kotlin, thus reducing the interest in using Scala in first place.

However as mentioned, they are doing cool stuff with capabilities at EPFL for Scala 3.

https://virtuslab.com/blog/scala/introduction-to-scala-3-che...