Earlier quoted context omitted.
I'm just guessing here, but I don't think that Apple is all that interested in making it easier to develop cross-platform applications. From their point of view, the best applications are OS-specific ones. So if you want a Mac application, you're best coding on a Mac, with Mac tools, and within that hardware eco-system. From this point of view, the same argument applies with Windows, Linux, etc... (albeit with the ca…
Apples interest in making cross platform applications easier waxes and wanes with their market share. If I remember correctly, they were quite keen on java and making it work well at one point.
You're right - they did have a Java-Cocoa bridge early in OS X, but deprecated it quickly when it was difficult to translate Obj-C semantics into Java. I remember trying it, but it wasn't really that easy to use. Even in this case though, the idea was to write Mac-specific applications, just in a different language. Most of the application's magic was still in the ObjC/Cocoa layers, which weren't cross-platform (or were they - I can't remember if there was a Windows port at sometime??).
While this would have made it easier to write cross-platform applications, realistically, that was never the goal. I think the goal of the Java-Cocoa bridge was to offer a backup plan in case too many devs didn't like Obj-C. At the time, Objective C was a novel language for many people. Once Obj-C got enough mindshare and it looked like it got enough of a buy-in from developers, Apple ditched Java quickly. I'm sure the licensing issues from Sun in the early 2000's didn't help matters here.
Also, it's only been fairly recently that Apple turned over the Mac Java port back over to Oracle. For the longest time, Java developers on Macs were always a version or two behind because they were on the OS X release schedule, rather than the Oracle/Sun release schedule.