> We see time and time again that even mission critical open source projects struggle to get people to fund it.

I think you've missed my point.

The problem (imho) is when actors that can easily pay, are avoiding it. And that's where a threshold of revenue (and also different tiers), feels more fair (again, from my perspective).

That is my point! We have to live in reality and in reality that does not happen. This dev is trying to get some sort of compensation for their efforts because the reality is the status quo is not working for them. We can "in a perfect world" all we want but we don't live in a perfect world.