Technologies that were considered "high-tech" 20-30 years ago are now accessible to regular people. Making DRAM. I remember a video recently of a guy making his own floppy disks.
Next I expect people to manufacture integrated circuits that have been discontinued. Like the Z80
It is not really feasible to fabricate usable integrated circuits at home. There is a huge difference between a one off demonstration of a principle that "sort of works", and perfecting the process to the point that it produces finished parts that can be relied on.
This guy is not exactly a regular person. He is a pretty unique case of a talented semiconductor engineer who has a home lab for side hassles. It is not a low effort thing. He runs the equipment 24/7, scrubs all the surfaces in the lab daily to keep it clean.
Still, with the lab and all of the equipment already at hand, it cost him several weeks of work to produce this demonstration of transistors and capacitors, which kind of work, but are still long ways from a "completely complete" 20 bit DRAM chip.
Unfortunately it is simply too much work for one person to maintain a viable semiconductor fabrication process, even when it is done semi-professionally.
