You can't give away everything and expect survival to continue.
If taken literally at face value, that philosophy would lead to a recursion loop of giving. Get food, give food away, get food, give food away.
You have to actually consume some of the things you acquire.
At that point, you are no longer technically paying it all forward, and at this point, a resource shortage will occur until no more resources exist unless someone (or something in a hypothetical robot future) expends energy to obtain them.
Now you got a dilemma. John produces X units of resources, but requires consumption 2X units of resources to survive. Jane produces 6X units of resources, but only requires X units for survival. Clearly Jane must provide John's missing X for him to survive.
Now, change the situation, where there are three possible end states. High Quality of Life (QOL), Low QOL, and won't survive.
John produces X unites, requires 5X for a high quality of life, 2X for a low quality of life, and anything else he won't surive. Jane produces 6X, requires 5X for a high quality of life, X for a low quality of life, and anything else, won't survive.
Jane now has a choice, have a high quality of life, and let John die (obviously a poor decision), or have a high quality of life and let John survive, or give John a high quality of life and maintain a low quality of life for herself.
What should she do? This is over simplified, but the essential state of the problem. Everyone working together to redistribute resources fairly based on needs hypothetically could produce a higher mode (most common value) for quality of life. However communism's planned economy hasn't had much success in long term survival as an economic model of government, since it eliminates an extremely strong motive to produce more resources (a higher quality of life being that motivation) since it their work no longer has a direct impact on the result. You'd need an internal reward system that rewards production of resources, not personal gain of resources, and we aren't wired that way.
A free market economy exploits that inherent desire as a motivation, leading to larger resource production in the society/species, but a huge gap in quality of life based. Moderated with some socialist policies, it allows an increase in the low resource producers quality of life while still keeping the the resource production motivation there for the high resource producers, ideally creating a net gain in quality of life (assuming that not all resources redistributed from the people they originally came from weren't increasing the quality of life in the same relative amount).
So... if we all payed it forward, ideally, if production did not suffer because of it, and planning was done to ensure all needs were met to give an equal quality of life to everyone, it'd be perfect.
Unfortunately, we aren't wired that way.