Addressing the question from this point:
leading on to a career change into photography
A photography career is actually not really about photography, thats just what you produce. A career is either getting a job from someone else, in which case you need to have self marketing skills, networking, and get lucky, or it's about creating your own business in which case you need all the myriad skills, patience, fortitude, and good luck to succeed.
None of that is possible without good skills as a photographer but where you get those skills from is largely irrelevant and measuring the cost effectiveness of the learning proces is highly subjective.