Scala is not in decline - as far as I can see it's on the up and up. Scala has its share of warts but that comes with maturity - I would lay money that Kotlin won't look so nice when it's gone through a similar amount of change.

Ceylon OTOH is at least good design, though I don't think that outweighs the library and tool ecosystem that Scala has.

Definitely not true. Scala is at its strongest ever. It's now possible to write frontends, backends, and mobile applications in Scala. There's an incredibly diverse and growing ecosystem of libraries. The Scala tooling has really stepped up.

The fact that there's so much discussion on the new SIP (Scala improvement process) and SLIP (Scala library improvement process) issues is a testament that Scala is alive and well. This is what happens in a mature language: many people put stakes in the ground.

Also, Scala most certainly has a bright future to go with its vibrant present. EPFL is hard at work with dotty, which will be a simplification and improvement of Scala.

Could you point an interested reader towards some stats :) ? I wanted to pick up Frege for a hobby project some weekend soon and would love to read more about the JVM up-and-comers.

No, I'll pick the next next one.