I'm not sure why and when exactly things have changed, but it looks that between pihut and amazon, not much "toyz" were left. I must admit though that the web has made it easier to learn/work alone; you used to go somewhere that taught you how to solder, somewhere that told you resistor color coding, tra nsistor number meanings, yadayada - now you watch it on youtube. The social aspect is gone; even makerspaces are often "just" the 3D printing and woodworking crowds, with little electonics.
It's worldwide. If it hasn't quite reached Japan yet, it will soon enough.
But we would need a local expert to verify
Economists since at least Adam Smith have noted that larger cities and regions can support a more complex and richer economic system.
One of California's problems is that rising real estate values and rents are both pricing out more activities (and people), and increasing costs of business: higher rents -> higher wages, the bulk of which are paid to landlords or mortgage lenders.
and see this discussion here: https://www.practicalmachinist.com/forum/threads/end-of-an-e...
Even in the 70s I'd find radio parts on "radio row" there.