Football is the most popular sport in the media, I pretty sure that by participation it's not.
We could make tiddly winks popular if we gave it the exposure football gets. Look at darts and snooker, when it had huge amounts of TV coverage, everyone was down the snooker hall and kids could all name Jocky Wilson and Eric Bristow, taken off TV and I doubt most kids could name one current darts player ( I couldn't )
A nice little table from wikipedia, show that if you look at TV coverage and Participation ratios that football comes out very poorly
I doubt the cost of football kit is any less than the cost to join a rowing club and use the free equipment, I don't have children myself but is the cost of soccer boot and strip much less than the cost of a bike (Halfords £109 )
Having has a QUICK look at the thread, there looks to be a mistaken belief by some that you need the super dupper carbon bike to start in the sport, which plainly you don't nor would a beginner need to buy sculls and the like.