Well I remember there being a time, when I was in middle school or so when the local radio shack sold at least Resisters, Capacitors, Multi-Meters, LEDs, small ICs like 555 timers, Piezo-electric buzzers, battery cases, solar cells, motors, breadboards, copper circuit boards, pcb etchant, solder, soldering irons, wires, shrink-wrap tubing, etc., etc.
Last time I wandered into one a few years ago I didn't even see *any* of that stuff. But they had crappy "realistic" radios. Great.
As for there not being enough people doing electronics as a hobby?
Well... to that I say:
1. If not, then it's the end of an era, and the chain can die a honorable death by sticking to their guns until the end.
2. I don't really believe this. Sure, people don't build computers and TVs from scratch with soldering irons anymore - but there is lots of cool stuff they could sell that is targeted as hackers/makers instead of junky consumer stuff.
3. If it's so, then it must be a US thing. We have parts stores here in Japan, and I have seen them in Germany in other places. They don't need to be as common as McDonalds, but there is normally a reasonable population to support them. If not, you're probably doing something wrong.