Few reasons...
First of all, you have any idea how much TV advertising costs, especially for an evening advert when school kids and teenagers will be in... Well, it will easily cost £100k for a bad 30 second slot, and £500k for a good one. How many players would you need to pay for that?!
Secondly, TV advertising generally doesnt work for participation sports - Why dont you see TV adverts for participating in ANY sports?! It just doesnt have a very good response rate.
Thirdly, its not very cost effective. There are much better-value-for-money ways of advertising. For about 0.1% of the cost you can advertise on the internet and saturate your field, or, hire people to stand in the middle of big cities and hand out leaflets.
The only exception to this was when Bravo TV and Channel 4 briefly ran paintball programs on TV, and advertised those programs. But I dont think thats what you meant.