Here's my $.02 so take it for what it's worth. If there was a demand for and support for the types of shops described, then they probably would still be around. Some shops, such as Retrogression are doing their best to cater to "serious" fixed-gear and singlespeeders. They do both walk-in and online business. No reason why anyone can't do business with them. So if you want them to continue, think about buying something from them, yes? I have no affiliation with them whatsoever, just in case someone wonders. They are just the first that comes to mind.

So if you are one of the luck ones that has a decent bike shop in town, you know what you need to do. If you prefer to buy everything from online discounters, then someday when you are in a fix and need that part today, guess what...