Starfleet Acadamy the only way?

FYI, there were other presidios in Spanish-owned California, not just in S.F. and Monterey. I understand that wherever the Spanish built a fort in CA, it was called a presidio. I've visited the one in S.F. & have visited a former presidio in San Diego which is now a museum.

RE: the Academy. My personal opinion is that there's only one Starfleet Academy in the Federation (in S.F.) where most Starfleet cadets go to become officers. Enlisted go through a different process. However, I think there's also a Starfleet Medical Academy. I don't believe going through the Academy is the only way to become an officer, but it's the method by which most Starfleet officers become officers.

Seriously though; last time we went through this, I reached the conclusions:
1) There are more than one SF Academy (concluded by: the population of member worlds, size of the San Fran. 'campus'...accomedations alone would be a nightmare, let alone class sizes...say, what's that building over in Paris France for anyways :confused: )

2) ROTCs ARE possible (BCIT, CalTech, MIT, and so forth [as Earth examples] would be able to turn out fantastic engineers. And they and other colleges and universities would be able to turn out science officers, medical officers, security officers, and so on; the student would have to take an ROTC in order to be an officer however. And there's probably a 'GI Bill' equivalent out there somewhere as well...say, minus the ROTC, 'GI Bill' grads could/would be the equivalent to enlisted, and would be placed/played as such...hmmm).

Now; to add this, for the variant to the old question:
3) Advancement of an enlisted person: two methods spring to mind:
a) Field Promotion: The individual is raised in rank and authority by a ranking officer, as means to better command of the rest of the troops and control the situation. This is usually occurs during times of war/battle, sometime not. It's also usually temporary, sometime not.
b) Traditional promotion: Through a combination of: good, hard work and diligent study, and enlisted person can rise to an officer rank, with all rights and privileges thereof. This is of course, a slow route, but (IMO) has the advantage of not going to the Academy (SF ships/stations/base have all the training equipment and facilities to do the training [Holodecks, LCARS computers, and other equipment]), but can contact SFA for clairification/explanation/assistance to any problems that occure during training onboard (sort of like what US does for the crew on submarines).