That is a true and good observation. Much depends on those kinds of people and those kinds of motivations.
But there are also the priests and doctors, from whom we reasonably do not expect to hear "this is all about my interest, what's in it for me?" And likewise there are many enterprises where people are doing them for reasons which do not relate to turning a profit, a category which a great deal of valuable open source development falls into.
Sure, but he doesn't say that self interest is or should be the only interest, only that markets and economic activity work best when self interest and the interests of society align.
Adam Smith wasn't a free market fundamentalist in this respect, much as the fundies would like to make out. He was very much in favour of regulation.
I like this:
"..The proposal of any new law or regulation of commerce which comes from this order [businessmen and traders], ought always to be listened to with great precaution, and ought never be adopted till after having been long and carefully examined, not only with the most scrupulous, but with the most suspicious attention."
And he was also an all-around pretty shitty economist, and those who claim he invented economics ex nihilo are delusional. He pretty much stole all the correct parts from other economists and added some falsehoods. His diamond-water paradox for example is retarded, and a step back from previous (mostly French) economists, since it's based on the Labor Theory of Value, which later spawned Communism. When I hear people praise Adam Smith I just want to NOPE out of the room.
It can be. If you believe that you cannot be truly secure in your freedom and well-being unless everyone around you is also secure in theirs, then helping people could be seen as "selfish". The problem is that we use the term selfish to mean whatever dickheaded move looks like it will net us some short term benefit. Without the ability to see all the indirect consequences of these selfish actions, we don't notice that the aggregation of them actually diminishes our overall well-being. Socialism, it could be argued, is based on selfishness as well, but paired with a recognition of our limited foresight and an attendant tendency to err on the side of mutual support rather than ruthless competition.
But there are also the priests and doctors, from whom we reasonably do not expect to hear "this is all about my interest, what's in it for me?" And likewise there are many enterprises where people are doing them for reasons which do not relate to turning a profit, a category which a great deal of valuable open source development falls into.