I think the difference is that over here, the company gives the tools to the employees. In the US, you have to bring your own stuff. Therefore, metrology equipment that belongs to single persons that retire lands on the free market.
Over here, the tools stay mostly inside the plants and are sorted out when the plants introduce new technology or new tools. But that´s just a wild guess from my point of view.
Concerning American tools, there´s a divide between the US/English toolmakers and the German/continental ones and how things are done. My guess is that it split up with the DIN and the introduction of the metric system in the 20ies. As an example, noone over here knows 1-2-3 blocks, they are just not usual. Yet everyone who used a pair of mine tries to snatch it from me. Next, they ask me where to buy them and I have to point them to an english supplier. Odd, but that´s the way it is.