Sometime I wonder, why Open Source has not flourished to SOTA in Chip Design. 5nm and beyond chips quote 40% as software cost out of a Billion $ cost to design the chip. That is a too large amount to attract somebody interested in open source.
IMO (i.e, not an expert, only fiddled around with IC design at .18 micron in undergrad), no fast/cheap try-observe cycle.
Software for web? I (often) can see the finished product as I'm typing the characters in my IDE. Even for PCB design? The output can be acquired and tested under a week with low cost.
IC fab? Not cheap and not fast. All built on machines and processes that discourage experimentation on running lines, since even the slightest mistake can scrap weeks or months of work. Work that involves high pressure, high energy toxic gasses, and lots of them. Also some non-toxic elements/chemicals. Capital costs are extremely high (IMO, this is also part of why working with HW doesn't pay as much - capital costs are high, allowing employers to have serious leverage).
IMO, that is similar to: why the James Webb space telescope cost so much, and why many Mars rovers cost so much. They have to get it right, at almost any cost, because it costs so much to deploy them. Unless a fundamental change in costs (w.r.t. Earth --> Deep Space) occurs, the cost of failure will remain high and so will the costs of development.
