To truly understand how massive the 2nd Keiba boom that Oguri brought forth, you have to look at this graph
You can point out which year the assets and the dot com bubble popped, but the reality is that Japan thoroughbred foals production was steadily declining after the 2nd Keiba boom, and is only slowly recovering from 2015 onward, but probably will never reach the 1992 peak again
However, whether Japan wants 10000 new thoroughbreds every year is an another question