For highly-specialized engineers and researchers, there’s often only a tiny handful of companies they could work for that offer jobs in their specialties. For example, if you’re a compilers expert, there are only so many companies that hire compiler developers, whether it’s working on a commercial compiler like Microsoft Visual Studio or contributing to an open-source project such as LLVM (Apple is a major contributor). These jobs tend to be concentrated in a few global metro areas.

Additionally, Silicon Valley in particular benefits from having multiple companies in overlapping specialties. Suppose I’m a GPU expert working for NVIDIA, and suddenly I hit a setback and it’s time for a new job. Well, Apple is just a few miles away, and Apple makes GPUs and NPUs, and so I’d have a shot at working for Apple.

Contrast that with people living in areas with little diversity among tech companies. For example, Intel recently laid off a ton of engineers working near Portland, Oregon. There are few alternative technical employers in the region, especially in the specialties Intel focused on in Portland. Those laid-off engineers are facing the prospects of pivoting to a different tech specialty with more employment opportunities, competing for remote jobs at a time when so many companies are requiring their employees to return to the office, or relocating from Portland, which is massively disruptive and can potentially be very expensive. Some may be forced to retire early.

Silicon Valley may be insanely expensive and ultra-competitive, but it also has critical mass, which is vital for highly-specialized engineers and researchers.

But only a small percent of people work in those highly specialized jobs.

Didn't Apple buy the CPU/GPU tech? I suppose the actual team could be located elsewhere.

I think the same can be argued for global investment banks. All of their important offices are in six cities globally: New York (Manhattan), London, Tokyo, Hongkong, Singapore, and Sydney. All other locations pale in comparison. Probably 1% of headcount (sales, trading, i-bankers) is responsible for 99% of revenues. There is a reason why investment banks are all crowded into very tall buildings in the same six cities: They are trying to access those "1% people". I see the same for tech clusters around the world. (For tech, I guess that less than 5% of staff generate most of your important intellectual property.) There is a reason why Oracle stays in Silicon Valley instead of moving to Montana or Oklahoma were real estate and salaries would be much cheaper!

There are plenty of other cities with enough job options that isn't something you only get in the bay area.

for the intel emplopees I doupt there is anyone else in the us who needs them. Maybe one or two to a military contactor but most have to find a new spectialty. I wish them luck. Fortunately specalists are mostly easy to retrain.