Even with the small sample and biased survey-taker, these numbers are probably correct--reality bears them out.
That said, by their own calculations that means there are about 70 million people with App Store accounts who would rather pay upfront for a game than play an ad supported game. That's not exactly a small user base to target.
Sure, churning out a simple, addictive freemium game that cajoles its players into paying to play is the easy road to riches. So is making cheap, crappy hamburgers and advertising them like crazy. And you're also competing with the "big boys"--you're up against Candy Crush Everything et al. It's like trying to open a new national cheap burger joint--you're going toe-to-toe with McDonalds, Burger King, and several others, who already know how to beat you.
This is proof there's also a very sizable market for quality games that don't treat their players like marks to be bled on an ongoing basis, just like there's plenty of room in the world to open a good restaurant or upscale chain that sells quality food for fair prices to people with taste.
You could also flip it around and say "86% of iOS gamers only game in small fragments of time, so intentionally or unintentionally have very poor value calculations when it comes to paying for a game rather than downloading something free with ads. The other 14% are gamers who spend more time or have better taste."
It's also worth pointing out things like the sketchy, sexed-up, free-to-play (but pay-to-win) MMORPGs whose entire business model is based around a small player base who dump huge sums of money into the game to stay ahead of each other while the vast majority of players pay little or nothing. They're just a more narrowly-targeted, blatant form of the same thing as Clash of Clans and Candy Crush are--basically a casino that gives away the cheap seats in an effort to draw in the gambling addicts.
Personally, the moment I realize that paid add-ons in a game aren't just there for people who are lazy, but are actually the intent of getting you to install the game, I will immediately stop playing and delete it. So I'm proudly in that 14%--give me a quality, meaty game for $10 (even $20, if it's big enough) that doesn't try to upsell me once I'm playing and I'll gladly pay it.