Lol no. Microsoft profits more than the value they provide, not exactly we should want to copy. We need to prevent hypercapitalism from reaching us in Europe, not make it worse, as we now seen exactly what it does to countries when you let it grow unfettered.
But I agree in general, governments and companies that use FOSS should donate back either engineering-time or money, but no need to do complicated "per-user per-year contributions", give them a sum per year, enough to fund the core developers at least and ideally to hire new ones, otherwise hire engineers and let them full-time contribute back.
Luckily, at least in Europe, this is exactly what we're seeing now. The governments who are looking into FOSS are all thinking about how to help fund it, no one seem to be thinking "How can we do this for free?" which is nice thing to see.