I don’t spend that sort of money now (I have 2 lessons a week for £12 a lesson), but I used to have about 12+ hours of lessons a week (that includes ballet, modern, tap, jazz and cecchetti), and more during festival season. It all adds up.
I completed the grades and got my teaching awards years ago. I am not a teacher (don’t have either the temperament or the ability for it - congrats to your wife for running a school
)