Who Develops Theories?

Really Influential Scientists: a successful theory has been developed by someone who is really influential (e.g. Newton).
However, a lot of other scientists have contributed to that successful theory. Evidence before the fact, modifications, and confirmation.
Me (and you): relatively senior people can develop theories and if they are seen as important, the person become influential.
You (me, and everyone): we have theories about how things work. It helps if we can make them explicit.
Fools: anyone can develop a theory. You have to be careful to evaluate them before you use them.