Given the linked article is about a 22 year old making a 1,500 transistor IC, etching wafers for a 40 year old with a FAANG salary doesn't seem that far fetched!
I think the CNC part is what’s interesting. A wet etch, or even a plasma etcher, is conceivable in a garage and are the traditional tools of the trade.
It'd have to be a really clean garage tho