Life isn’t a zero sum game where you have to optimize material wealth. Some people do things for others just because they like doing it, because they have the means to do so, or because they simply want to help others.

Sure, there are costs involved, but that’s true for literally everything if you account for opportunity cost. The vast majority of people choose to waste time completely unproductively, with no objective benefits to their lives (often with objective disadvantages), so is it hard to imagine that some people aren’t like that and instead choose to help/provide for others whole perhaps having some other non-material benefits like learning something or just becoming liked within a community?