As @rhendric said, simply fund that work to be done by professionals with relevant experience. I estimate that cost to be somewhere on the order of 500k EUR/year for 2-3 years to make a tangible difference, i.e. a couple of full-time engineers who know what they’re doing.
If you compare that to Determinate Systems’ original funding or the amount of skill and effort put into Lix so far, this is about what to expect from Nix if we had that.
I’ve helped raise (and spend) roughly half of that over the past 2 years, but due to particularities of how that funding works it wasn’t and still isn’t possible to focus it (exclusively or at all) on well-understood core problems, and I feel it every day. Collectively all volunteers already contribute in-kind at least an order of magnitude more, but on very different things mostly outside of Nix itself, and with barely any coordination. This is why the pace is glacial. Everyone who works with me knows this is not for a lack of trying.
Remote source management (one issue flakes tries to solve) is only a small part of those core problems, the installer is also one, evaluation performance and caching, code organisation and information architecture, tooling support, security updates, contributor workflows, and even seemingly unrelated things such as how budgeting and accounting inside the organisation works. Those things need to be thought through and built to last.
You will notice that @grahamc and his team are addressing exactly those items, but independently, and he repeated in this thread once again that it’s to work around a lack effective and timely decision-making upstream.
I attribute this situation to a lack of a sustainable business model (i.e. a deliberate handling of revenue and spending) for the foundation and, for what business model there is, a lack of consistent execution. This can be fixed in a straightforward fashion with the right investments (and I’ve made several proposals only recently). One barrier to that, as I’ve experienced in the past, is simply trust: there are risks to take.
The community put trust in the steering committee to make the right decisions, and this is great because finally there’s no ambiguity over who’s in charge. Clearly — and this was to be expected from a group of 7 volunteers — they’re bottlenecked on execution. Who would you give that authority to execute?