X2. The average personal trainer at LA Fitness or Equinox is not making 250K a year, UNLESS they also have their own business on the side.
Thus, it ALL depends what you do with it. Again, the average trainer who works in a gym (in which he does not own) is definitely not making 250K a year. If they are, its EXTREMELY rare. If you have your own business, of course you can make a killing.
I don't know this for a fact, but it wouldn't surprise me if the big chains have no-compete clauses in their employment contracts.
As far as trainers making 250k, maybe a few "celebrity" trainers. The real question is what the median trainer makes and the benefits they receive. That's what makes Training a bad career choice: having to be an exception to make a good living.
When I did training, in the late 1980's, I worked in one of the biggest, most well known health clubs in Manhattan. The club charged the clients $30hr and gave us hard working trainers $8hr.
Some of the other trainers cut cash deals with clients on the down low, but, sneaking around isn't my style. So, I moved on.