I think the people flock to JDM motors because most wrecking yards in the US (not a "you pick it") want to charge a fortune for parts. Hell, i'm looking at car-part.com and there is a listing for 1989 "7MGTE, RUNS PERFECT" 120,000 for $2000. Why buy a motor from one of these people for the insane money they want, when you can get a reasonably priced motor that usually has decent mileage for half that? Sure, you have to swap over your sensors, etc but still. A 7M is a 7M regardless of what part of the world its built for.
Hell, I try and buy JDM motors just to stick it to these junk yards that are out to rob the average person.