Hi,
To me it comes down to the question of adoption. Do we want people to adopt the new Jakarta REST 4.0 specification? If yes, running on Java SE 17 seems like we would get the most adoption.
It's similar to discussions that we had since about Java 1.2 really. Back then it was staying on Java 1.0 vs adopting Java 1.2, and not even that long ago in Java EE 8 staying on Java 6 vs Java 8.
Eventually, was it ever an issue?
For some customers, it definitely was.
I mean, JDK 21 was released, instead of putting more time into JDK 17. Why did the Java SE team even release 21, if putting more time and energy into Java 17 updates would mean larger adoption of Java?
Or would pushing the ecosystem forward eventually mean more adoption?
That's impossible to say. Looking in the past though, corporations and government agencies are slow to adopt new things. Does that mean they may be slow to adopt Jakarta REST 4.0? Probably, but the least barrier of entry the better. Again, only Jakarta REST and Jakarta Concurrency are the only two individual specs moving beyond Java SE 17.