>If you think Ubuntu provides you with $X in value but you literally do not have $X to your name, well, I'm not sure how it could be providing $X to you, then.
I'm not sure I follow your reasoning.
Imagine I have disposable income of $0 and I currently use Ubuntu. By your reasoning, Ubuntu is worthless to me. However, let's say that if you offered me $1 to stop using Ubuntu, I would say say "no". We can safely conclude that Ubuntu is worth more than $1 to me, even though I don't have $1 to pay for it.
Ability to pay doesn't always equal value created. If I like take walks in a national park, I obviously derive value from that resource, but I don't pay anything for it and it doesn't allow me to generate any additional income.