What happens when the foundational premise is wrong?

An interesting experience.  From personal experience, I know Tokyo as an infamously expensive city but that is based primarily on experiences from the 1980s and 1990s.  I am consequently taken aback by Is Tokyo really a YIMBY success story? by Tyler Cowen.

It is common lore in YIMBY circles that Tokyo is such an inexpensive city because Tokyo/Japan has allowed so much freedom to build.  Sometimes it is mentioned that Japanese building and regulatory decisions are made at higher levels than the strictly local, which lowers the power of the NIMBYs to restrict building.

I don’t doubt the key elements of this story, namely that Tokyo real estate is relatively cheap, and also that it is relatively easy to get a certain kind of construction through, including vertical construction, both up and underground.

The whole YIMBY vs. NIMBY conversation is clearly of great import to Cowen.  I regard it as often irrelevant and hardly ever of significant value from a framing perspective.  

And in this case, it seems completely off-base since the premise - "that Tokyo is such an inexpensive city" - seems so incongruous with my recollections.  

While Cowen may often have some curious arguments, he also generally has pretty high quality commenters and they come to my rescue.  Clearly things have changed since the 1980s and 1990s.  But also, perhaps not all that much.  There seems to be a fair amount of argument that Tokyo is still at least as expensive as most its peer global cities and perhaps still somewhat more expensive.

The entirety of Cowen' speculative argument is undermined if the premise is untrue.  

But there are many interesting issues raised that still make it a worthwhile intellectual conversation.

One thing not discussed explicitly is the temporal aspect.  If Tokyo was indeed as eye-wateringly expensive as I recall in the 1980s and 1990s and it is now just expensive, what is the elapsed time window over which one might see distinctions between the impact of NIMBY versus YIMBY strategies.  Once again, I think the YIMBY/NIMBY is the product of closeted intellectuals with too much imagination and not enough experience.

But if we accept that there is something real there, how long would we expect it to take to see some consequential change.  Specifically, IF Tokyo was 50% more expensive than a comparable global city in 1990 and IF in 1990 they decided to undertake a public policy of either NIMBY or YIMBY or some combination, how long might it take for the consequence of that change to show up in the aggregate averages of a 15-40 million person city (depending on definitions)?  

If Tokyo has come down from prohibitively expensive in 1990 to just very expensive in 2023, that is a 33 year window.  Probably should be shorter as the 1997 Asia Financial Crisis marked a turning point for Japan and many other economies in the region.  In addition, the rise of China really began to take off in this time frame.

Let's go with 1997, so, a gross city cost adjustment over 26 years.  A period in which commodities became cheaper, Chinese manufacturing drove down costs, a period of rapid aging in Japan, plus various other exogenous events.  

How would we tell whether and to what extent NIMBY/YIMBY was even a factor affecting Tokyo cost of living and cost of real estate.

Yes, at the margin, YIMBY/NIMBY probably has some marginal insights.  Still strikes me as intellectual self-stroking.