There are 2 probable reasons.. one you cited, and, possibly , the greater reason.

A very high percentage of salsa " teachers ?", had/have no formal training, so, never being exposed to 2, either in dance or teaching, the easy way out, was "1" ,because thats the way THEY were taught .

And , is 2 more difficult than 1 ?.. not necessarily, it depends how its approached, and, by whom is doing the teaching .

People even complain about not being able to find the 1 . So, its much an individual thing .

2 points....

You CANT dance mambo to ALL salsa music, much of it, is written in a different musical format, and would make little sense for interpretation, musically speaking.

By the, way you hi- jacked the posts.. it really was about Rumba