I completely understand the sentiment. And it's something that's been tried (although bits and pieces, for different reasons). Though never elektron.
I'm personally not moved. As a python and C++ developer I find javascript to be the most clunky language with popularity. It's worse than C++11 on the fundamentals (inkscape's current language). The momentum behind Inkscape's codebase would mean a js version would always be a ground up recreation anyway.
Martin have you looked at Typescript. It's very close to C++ and the refactoring support in VSCode is quite good. Not sure if Gravit uses it, but Gravit is a very good backdrop as to what is possible:
Another interesting thing would be to have mini sub assemblies of Inkscape C++ vs. Inkscape V8 (Javascript) just to compare performance and code modularity / foot print size.
Cheers,
Ole