It's both an argument about proportion and also national will and commitment.

So what? A small, poor country with a lot of national will and commitment might punch above their weight in funding their military. But that doesn't suddenly make them more important to NATO forces that the large rich countries. If you keep thinking that NATO is nothing more than the countries you esteem because you like their "national will," rather than looking at what their actual military forces are, you're going to get a very flawed understanding of the situation.

You're making moral judgments about the countries and whether they live up to your sense of fairness, and then mistakenly assuming that those moral judgments translate into their actual contributions to NATO.

I should hope that Germany, France and the UK can field much more than the Poles. That's not the point. The point is that those three a) have been coasting for decades b) would rather not do anything to improve their militaries and c) lack the national will to act even if they could.

That's not the point you made. You didn't make a point about whether Germany, France, or the UK are living up to some "fairness" obligations, or have some inchoate "national will" quality that attribute to the Poles but think is lacking in those nations because you disapprove of their budget choices. You made the point that NATO has been reduced to just the Poles and the Balkans - which is completely and totally wrong. Whether you like their "national will" or not, Germany and France and the UK are much much more important to NATO than the Poles. They provide much much more military resources to NATO than the Poles.

Oh, and your characterization of what the UK/France/Germany can and can't deploy is something you should research using better sources before you criticize anyone else's.

To wit: Poland has more main battle tanks as of 2021 that those three combined.

And a small air force and virtually no navy compared to those three combined. If they've got such "national will," why haven't they upped their naval game? Or built an air force to match their battle tank capacity, instead of having to rely on air power coming from France and Germany and the U.S. in the event of Russian invasion?

Once again, there's a reason why they have more battle tanks but modest air or naval resources compared to the other countries. Because they're close to the possible front with Russia and the others are not, and air/naval resources are much more mobile than tank command.

This is not some kind of moral superiority. It's the appropriate allocation of military resources among countries that are intended to repel a continental invasion as part of a multi-national coordinated fighting force and not as stand-alone militaries.