Bell was initially strong in science and music theory. The reason he was able to actually end up with the first practical telephone, was that he then also learned electronics. You really need both to develop a ttelephone.

Bell then did a lot of public shows to promote the telephone. It was certainly usefull that Bell worked as a teacher earlier.

That is actually extremely common for big leaps forward. A lot of those just combine knowledge from different domains in a new way.