Yes, VSCode will be replaced by something newer and flashier, but the learning curve to switch to it will be minimal.
It's a plugin management system that happens to be shipped with a set of plug-ins targeted at serving as an IDE, written in Java instead of Lisp.
Ah, but you miss its hackability aspect by virtue of being a lisp runtime. I wouldn't say eclipse is anywhere close to "hackable" as emacs is.
Just run C-x b <scratch> RET and you have an elisp buffer to manipulate the state of the entire editor. It allows for superfast iteration, compared to the plugin development cycle of other editors. Though, vscode/javascript has definitely made it much closer to what is possible in emacs.
IMHO, the barrier to entry for modification for both emacs and vim is much lower than their competition: evaluate text in a buffer, observe change to your editor
I don't know of any other tooling has that immediate feedback loop remeniscient of the old JS in HTML (or the dev tools console, as apples to apples) approachability
An exaggeration, but not a large one.