He gives her a flower, she gives him a smile. We give him a push to start his engine. The farmers give their crops to producers, they give their products to stores, they give us our daily goods, as we give our time to the company, the boss, whatever. An ant colony isn't just a bunch of ants, it's what they are doing together. We give things to each other for many different reasons.
Persistence depends on the continuing viability of the process.
Gift exchanges persist because, on balance, each person in the network finds their self interest better served by continuing than withdrawing. They desist when those who are most giving find it isn't working for them. If those who are giving are in consequence recognized or acknowledged or credited in such a way that they might expect to receive gifts in turn, then their persistence is encouraged. In our present socio-economic world, the most common form of such recognition is money. Money, in one form or another, is the thing that keeps most people doing what they are doing, serving whom they serve.