But no one is being paid when a theorem is used, and that is why we use them so freely for everyone's benefit. The only incentives are quality, recognition, personnal accomplishment and general welfare. The main advantage is that scientists, or free programmers, take the time to do things right, and to redo them. Quality is the ultimate goal. Industry, on the other hand, has all kind of strange constraints, like time to market, or doing it like the guy next door.
Money is the ultimate goal.
The main reason they buy some software is because others are buying it, even when they know it is not the best. The same holds with technological choices. But free programmers are free in many senses, including the freedom to chose the right solutions over the popular ones. If science had stuck to popular solutions, the Earth would still be flat. Industry as a whole is a completely irrational structure, even though individual decisions are rational, because its individual components keep playing some variant of the prisonner's dilemma with the globally losing strategy.