Just a little turn on your wording...
I want to write code and build things for myself, with hope that this code will be beneficial to others as well, but it doesn't have to be. Even better, if writing the code for myself can provide a life for my family and I, and also be beneficial to others.
I've heard it said that even philanthropy is as much driven by the individual philanthropist's need to feel the good feeling of giving, as it is by the actual or perceived need of others outside of the philanthropist. Sometimes goodness happens through the alignment of personal incentives with those of others, sometimes it is purely personal, but you probably need a blend of both to survive physically and emotionally.
There's a lot one could consider and digest in this thinking - open source vs proprietary, for vs. non-profit, side projects for fun vs. for profit (and where those blend together sometimes), "freedom" and much more.
I think a lot of this is about opening up yourself. It seems you're doing just that with your current endeavors, and I applaud and congratulate you for it!