If cyclists want something fixed fast (ie on a commuter bike), they buy the part on the internet, or on the way back from work, and mount it themselves in the evening.

Also, there is still a load of retro design in bikes. I'm a student, and I don't have the hotest model from the most popular brand, for exemple. I have a 1990s road bike, and a 2014 trekking bike with stuff like threated bottom bracket, for exemple.

Lastly, a shop that is able to tune a old headset with the 32mm wrenches, straighten a wheel perfectly, and know that your handlebar is probably 25 mm wide, and not 26.5mm like you ordered (or the vice versa), is greatly appreciated. I've seen franchises that were unable to do that.

So shops with experimented people are the place to go.