There are a bunch of different problems better described as "off-cliffs" than on-ramps; initial syntax / conceptual complexity is one, build systems are another. Not that other ecosystems are necessarily better. Modern web dev is pretty damn confusing for beginners as well. I helped an ex-girlfriend as she went through a coding bootcamp. Very little of the material stuck and it wasn't her fault. The whole stack is just far too complicated.
The biggest issue for teaching Java is IMHO not really the syntax of hello world - as Brian says, teachers can handwave this by saying they'll explain it later. It's worth improving mostly because it helps regular programmers who want to use Java in a scripting-like way. The more fundamental difficulty that newbies have is showing other people what they've done.
In the old JRE days it was easy - just send them a fat JAR that opens up a window with Swing and does some cool stuff. Your friends/parents/teachers/etc would probably have a JRE installed already and it'd all just work. In recent years they've abandoned the idea of a JRE and JARs as an app format. You can still open up a window with Swing or JavaFX and get scribbling, but now to show anyone what you did they want you to bundle the JVM and make a more 'native' style app with it. There's a lot to recommend that approach overall, but it's unquestionably harder for learners.
Last year I was discussing this problem with Dmitry Jemerov (product manager for IntelliJ). He sees this issue directly - learners download IntelliJ, get some cool pixels on screen with Swing or JavaFX and then hit a brick wall when they want to send their program to other people. They ask around and it becomes "oh why aren't you learning web dev?" and then they balk when they realize that involves learning 3 new languages and maybe server sysadmin stuff. App stores don't help here because Apple/MS don't like their nice discovery system being gunked up with "my first code" stuff. Even if they stick with Java and try to learn jpackage they quickly realize they need Windows, and a Mac, and maybe Linux just to make packages that their friends can run at all, and then having done all that there's no way to push updates!
We were discussing this problem in the context of maybe doing integrating IntelliJ together with Conveyor [1], a tool my company has been writing that makes desktop app distribution drastically simpler. Actually if you are OK with self-signing it's no harder than compiling Markdown to HTML is, the workflow is very similar. Even if you want to sign it's still very easy; the hardest part is just the general bureaucracy involved with buying the certs. It works for any kind of app including Electron or native apps, but of course with a JVM app you don't have to cross-build anything and Java GUI toolkits are a bit easier to learn than web dev.
There's more work to do here, for instance drawing icons is tedious and when learning a distraction, so we've got a feature in development that draws icons for you. And whilst you can upload the resulting package repository to GitHub Releases, that's not automated and it could be.
I think we're pretty close now to basically abolishing this on-ramp/off-cliff, at least if your users are willing to copy/paste commands to the terminal (due to the self-signing; if you supply real code signing certs the UX is obviously much nicer). Getting rid of the code signing requirements means sandboxing but that's a bigger lift.
BTW - Conveyor is actually implemented as a parallel incremental task-caching build system, internally. We've generalized it and are currently experimenting with that for some of our own build needs. We're some way from being able to replace Maven/Gradle but totally agree that usability of existing build tools is very poor. Usability is in fact the primary ground on which this experimental build system differentiates.
[1] https://conveyor.hydraulic.dev/