I guess you didn’t know this, the idea is strength in numbers. If you can’t provide for personal and collective defense, gtfo.
When I hear phrases like strength in numbers, I think of elephants. When a herd of elephants watches lions circle their community, the strong ones stand around their young to protect them.
That's analogous to "strong" countries subsidizing ones who can't provide for themselves, because having an allied presence is helpful.
When that is said, its good that most NATO countries are hitting and exceeding 2%. It's clear that Europe can not rely on USA to be the "world police", we need to be be able to defend ourself.
Also, friendly reminder that article 5 has been used exactly once, and that was to defend USA. Soldiers of my country has died defending USA.