I've been a student at an Arthur Murray studio for about 2 years and my own personal observations of "teachers in training" at the AM studio where I attend are as follows... there has been about 6 teachers(male and female combined)that were hired and 5 have been terminated in that time period. Having said that, I believe those terminated were not meeting the expectations of the owner/manager for example, students didn't want them as their teacher, they did not get along well with staff/supervisors, they couldn't learn to dance or teach dance quickly enough etc. or the image they presented didn't fit the AM image.
The one teacher (still employed) was an AM student about 1 year before getting hired as a teacher in training. Other teachers working there long term (also those competing) it seems were previous AM students for a few years with lots of previous dance experience(ballet, jazz etc) and then applied to become teachers and have been working about 5 years since they were hired.
You must remember that AM is a profit driven business and you will be expected to progress quickly, work very hard, and your pay will be very little given that you are getting $$$'s worth of dance lessons.You probably won't be subsidized by the studio to compete as a pro for at least a few years(or until you are able to generate adequate $$$ for the business)
Didn't you get terms of employment by your AM supervisor about expectations?Also remember, you must have had enough skill/personality that they were willing to invest in you by hiring you in the first place. I think if you're a hard worker, motivated, likable and have the ability to dance and learn quickly you will be successful.
Good luck!