Where I live, at least 25% of lead climbers do at least some trad climbing (there's just so much of it in Squamish and you'd be missing out on most of the multi pitch if you're just doing sport).

But for argument's sake, let's say 5%. That's still 5% of climbers who are likely to spend more in a year on equipment than 99% of people who play soccer ever will. That's why I'm saying it's a sizable industry when you look at what people are spending.