When I moved to the 'valley of the nerds' in the 80's there were dozens of places where you could buy electronics at "retail" prices, and there were places where companies disposed of electronics they weren't going to use for "scrap" prices. This is where the places like WeirdStuff, Halted, Zacks, Alltronics, and others thrived.
There were many manufacturing companies that did prototype or small run manufacturing. There were companies that started up and closed down. There were labs that were opened, closed, or changed in some way. It lead a bunch of places where used (sometimes lightly and sometimes not so much) gear and parts were bought for pennies on the dollar and sold for nickels on the dollar.
The really cool thing about the "surplus" market was you could walk through isles of stuff where parts that someone payed thousands of dollars to have machined were selling for a few tens of dollars. Chips, like FPGAs, that were $1500 each selling for $5 each. Connectors, switches, transistors, and all sorts of discrete components that sold very cheaply. The good news was it was cheap, the bad news was that when they ran out, they were not getting any more in.
I bought from them, I sold to them, they were the source of many a project which could be built cheaply because you weren't paying full freight.
A number of things have conspired over the last 20 years which changed this world. Of course part of it was that a lot of manufacturing went off shore. Now when someone had to by 50,000 chips to build 45,000 units, the 5,000 they had left over ends up in the stalls at Shenzen not the shelves of a surplus store in the Bay Area. Another factor was that after the turn of the century parts became more specialized and manufacturers more secretive so while a complete data sheet of an Intel video controller was available in their data books, register level access to the NVIDIA or S3 chips was protected by strict nondisclosure agreements. The other change was that as manufacturing moved, the things that supported them moved, calibration labs, certification labs, PCB manufacturing, and assembly. So what was a steady stream of 10 year old test equipment that had been shuffled out of these places because the new stuff could hand the new speeds etc, that started drying up.
The typical experience of walking into one of these shops were aisles and aisles of "stuff" from compoents, to partial assemblies, to full assemblies. I walked into Halted one day and they had three pager transmitters that someone had surplused out. With the three of them you could easily create a single working one with some spares and set up your own private pager network. When the company that made Ricochet modems (an old wireless peer to peer networking systems) went bust not only did their modems show up in the surplus market but so did test equipment for characterizing their power output and frequency spurs. Stuff that an RF lab would pay $50,000 to put together yours for the low low price of $1,500 or so. Sometimes you would come across really cryptic, possibly alien, artifacts. For example there was a stainless steel clamp with a micrometer dial attached to it where a position adjustment would be made. The dial moved freely but it didn't seem to adjust the position of the clamp. I figured it was a manufacturing defect until a friend of mine pointed out the units on the dial was angstroms. We figured out that these were part of a fixture for making optical cables and would help align the fiber and connector in terms of nanometers (a very very small amount). One day we went to the new arrivals table at Weird Stuff and they had a complete seeker head for an AIM-9 sidewinder missile. They were asking $5,000 for it (I offered them something silly like $500). The next week it was gone and I asked if they had sold it, the clerk said no, the bureau of Alcohol, Tobacco, and Firearms had showed up with the FBI can confiscated it. Apparently it was possible to derive classified information about the missile by looking at the seeker head.
At the turn of the century during the Y2K period hundreds of computers that the manufacturer was unwilling or unable to make Y2K complaint showed up. This included PDP-11's and MicroVAX systems. I ended up with an example of every QBUS based MicroVAX ever sold by DEC. They were kind of like pokemon monsters, at some point you felt you had to have one of each.
These days most of the startups are purely software based. And their infrastructure they rent from Amazon or Google or Microsoft. Those companies have recycle programs that cut out the surplus vendors and usually don't leave anything usable. When a typical Silicon Valley company decides to "sell off their assets" that generally means office chairs, white boards, and the occasional espresso machine. Not test equipment, test fixtures, extra parts, and tools. And it is also true that fewer people are trying to put together an EE lab or RF lab on the cheap, or get their HP^h^hAgilent^h^h^h^h^h^h^hKeysight test equipment calibrated. Chips are either cheap and commodity from places like Digikey, or they are expensive and only obtainable through a mutual NDA with a company.
So the era ends as the long tail stretches into the future. It is sad that folks here won't be able to experience the Silicon Valley that I did but by the same token my version of the valley was different than the semiconductor manufacturing version (60's - 70's).
Maybe it's time to consider moving to Shenzhen. There certainly does seem to be a thriving maker and hacker community there.
The only real way to buy industrial parts and equipment is to live in a big city and attend industrial bankruptcy auctions. Most of the time it's machine tools, but occasionally a prototyping shop will go bust or a local university will do a surplus sale. These are the only real way to get decent gear reliably I've found.
I’m sure things are even weirder in Asia.