It's not a standards issue as the Lexus LX is basically the same thing, they probably think it's better to only sell the Lexus to Americans.
The LX always sold better than the Land Cruiser for some reason. I see 100 and 200 Series LXs all over my town. I know of dozens of each. But I am only aware of maybe 10 total Land Cruisers.
When I ran an import repair shop, we had plenty of clients with the LX but myself and 2 other clients were the only ones with Land Cruisers.