I'm not sure about popularity, every school kid in America does bicycling... just not with all the fancy extras.

In running, it is all about shoes. Yes, there are shorts, shirts, and sweats, but your shoes are primary with color, style, and fit being important.

In bicycling it is all about the bicycle. I'm not sure how long I'd stay in a bicycle store that was wall to wall shoes.

A bicycle in a bicycle store may be just window dressing, but it is a very vital part of the window dressing. They are nice to look at, but they also show off the latest and greatest components.

However, my primary bicycle was purchased used over 30 years ago. Over that time, I've spent the purchase price many times over on things like tires, tubes, rims, wheels, spokes, handlebar tape, brake pads, toe straps, panniers, replacement derailleur, chains, etc. The list gets pretty long.

I do carry-out, and never have a shop do maintenance for me. I'd even buy a tube carry-out for an emergency flat repair, but "service" is also a component of successful shops.

Anyway, there is a niche for all. I think companies like Shimano are actively trying to choke off their internet sales of shoes. I think it is a crazy idea, but I think they wish to prevent a person from going into a store, wasting the sales staff's time trying on a bunch of shoes, then going to buy them on the internet.