There are plenty of people who aren't interested in using languages with proprietary toolchains. Those people typically don't use C#. The people who don't mind proprietary toolchains typically write software for an environment where D isn't relevant, such as .NET or the Apple world.
One of the issues I've seen in the community is just that there aren't enough people in the community with enough interest and enough spare time to spend on a large project. Everyone in the core team is focused on working on the actual language (and day-jobs), while everyone else is doing their own sort of thing.
From your profile you seem to have a lot of experience in the field and in software in general, so I'd like to ask you if you have any other advice for getting the language un-stuck, especially with regards to the personnel issues. I think I'd like to take up your proposal for a web framework as well, but I don't really have any knowledge of web programming beyond the basics. Do you have any advice on where to start or what features/use case would be best as well?
Currently we need to get a stackless coroutine into the language, actors for windowing event handling, reference counting and a better escape analysis story to make the experience really nice.
This work is not scheduled for PhobosV3 but a subset such as a web client with an event loop may be.
Lately I've been working on some exception handling improvements and start on the escape analysis DFA (but not on the escape analysis itself). So the work is progressing. Stackless coroutine proposal needs editing, but it is intended to be done at the start of next year for approval process.
I honestly think if Walter Bright (or anyone within D) invested in having a serious web framework for D even if its not part of the standard library, it could be worth its weight in gold. Right now there's only Vibe.d that stands out but I have not seen it grow very much since its inception, its very slow moving. Give me a feature rich web framework in D comparable to Django or Rails and all my side projects will shift to D. The real issue is it needs to be batteries included since D does not have dozens of OOTB libraries to fill in gaps with.
Look at Go as an example, built-in HTTP server library, production ready, its not ultra fancy but it does the work.