Loom doesn't need to pose any issues for Kotlin. If you target only the JVM, you just use virtual threads directly and ignore the coroutines stuff. If you target other runtimes you use them. If you use a KMP library, just surround stuff marked async with runBlocking {}.

SIMD/Panama stuff is just new APIs. No problem there. Kotlin maybe even wins because Panama is super verbose.

JVM value types seems never to arrive. Stuck in dev hell for years maybe. If/when it ever does see the light of day, Kotlin has value types and so it can just be compiled to a JVM value type to get the benefits. You'd need to opt in to an ABI break but no big deal.

So the binary compatibility part hardly seems an issue even looking forward a long way into the future.

It's probably harder for C++ because the language there seems to evolve quicker than Java!

What Kotlin calls value types aren't the real deal, just syntax sugar for primitive types with method with a single field.

KMP taken to the extreme, is better for Kotlin just to do its own thing with Kotlin/Native, except it is so behind that JetBrains is using Rust instead for Fleet services.

Java is expected to have language level support for some of those features, will Kotlin catch up?