Ole,
Such a large project needs buy in from developers. It wouldn't even be a fork, it'd be a whole new project.
Martin - yes exactly. Something that can be iterated on slowly and hopefully draws in new experienced Javascript developers. There is also a large market for cloud vector graphics, so sponsorship should be easier.
So you're asking for developers to start a new project and not work on Inkscape any more.
Not at all. You can have two versions of the same app. Eventually this will be done under Inkscapes control or not under Inkscapes control. Inkscape is built on old tech. Inkscape can take control now and start reinventing the platform, or wait until someone else does it, and become irrelevant.
I don't think the project's best interests lie in abandoning the project.
It would be an enhancement. Expand the developer tools, expand the developer pool, expand the use cases, expand Inkscapes shelf life, expand the ecosystem of SVG components. AND nail your concern about Inkscape being able to run on any platform.
Cheers,
Ole