Hi arider,
Here's the tip, only get into the business side of kiteboarding if you are extremely passionate about the sport. Do not expect to make a lot of money at it. Most people earn less that the average wage after taxes and costs.
I think that the growth of the sport may be showing signs of slowing. We only did same number of lessons last year as the previous one, partly due to weather considerations and partly due to an ease in interest.
By all means the sport is fun but making it your business changes everything.

Expect to ride a LOT less, work harder than you ever have, have less time to yourself and live on less money.
With new brand coming into the industry everyday, the market is becoming extremely diluted and there is price warring yet to come I believe, as all of the little unknown brands fight for a place in the market. I reckon it's going to get quite cut throat over the next couple of years and we will see more and more players businesses turn toes up once they have enough of working their guts out for little reward.
Lots of people get into this sport thinking it is a gold mine and that you spend everyday on the beach and ride heaps. It doesn't take long to figure out that this is a myth and that its just hard work.
Income is feast and famine due to the seasonal nature of the business, just like the snow season. If you are looking for a good ROI, I'd suggest looking for something not weather dependant.
This is why I suggest you do it because you love the work and want to do it because you are passionate about helping people into the sport.
Good luck,