When I go to a new town (like New York City), I try to check out at least one local hobby shop to see what they have.
I'm always disappointed.
Why? Because most all have the same stuff they have had for years. The same WWII replica plane or conventional helicopter.
They generally have few multirotors. But when I look around, I see multirotors being sold at Fry's electronics, they are in the news all the time, there are now 3-4 times (by my estimate) more MEETUPS that involve multirotors compared to conventional R/C.
I'm certain that one reason for the popularity is the fact that you don't need a landing strip for a multirotor. And they are easier to fly than a regular helicopter. Also the fact that you can buy a tiny, entry level craft for under $50 and "graduate" to bigger craft with cameras later. The "cost of entry" of getting into quadcopters is cheaper than buying one of the old control-line airplanes that I tried to fly as a boy. The difference is dramatic if you consider inflation. And that control-line plane didn't do anything but go up and down while it was flying in circles around me. Boring!
I bought some ESCs from China recently. They were pre-programmed for LiPO batteries - but for defaults had very slow response to input changes, brakes ON and a "hard" cutoff at 11V. Not something you would want in a multirotor! And to top that off, you couldn't re-program it to be useful with a multirotor without buying one of their programming cards.
And I saw a motor that would be great for a multirotor on EBAY. It was at a great price, so I went to bid on it. But the only quantity I could buy was ONE. In order to buy more, I had to buy the one item 4 times. I tried to get the Chinese merchant to bundle the shipping, but they told me they couldn't do that (because they were already packaged for shipment in prepaid shipping boxes). So now, the 4 motors would have a shipping cost of $40. I didn't place the order. Why don't they "get it" and sell these things either as one OR four (or maybe 5, so you have a spare)?
And when I'm at a hobby shop in the US, and I ask why they don't have more multirotors. The reason they often give is
"We don't have that many people asking for them".
No wonder. I often use a statement that probably fits well here:
A Chevrolet dealer might think that very few people want Fords, because no one ever comes in and asks for one.