Well way back in the 80s, most MDMA in the US was made in the US and it was cheap.
In the 90s we started seeing large scale manufacturing in Europe and must of the E here was imported from europe...By the late 90s it seems to me that the boom in E use started shutting off the supply from europe, choking the supply, and increasing the price.
The simple facts are this. Virtually all MDMA consumed in the US is not made here. The precursors are impossible to get, as mentioned before. In europe, as others have also said, the precursors are much much easier to get and simple bribes keep the police at bay. Massive supply, easy production and distribution = low price.
In the USA, it is my suspicion that since about 2000, much of the E we get here is produced in canada...some now from Asia....my bet is that MDMA powder is produced in eastern europe, smuggled into canada, where they are generally mixed into crap pills, pressed (pill pressers are easy to get in canada, yet again impossible in the USA), and then smuggled into the USA. there are several main distribution points in the USA and then those pills have to pass through many hands, large distances, and much risk to get to your hands.....therefore the price is high.
Its much easier to drive a car though a checkpoint from estonia through germany with a ton of pills than it is to fly/ship those pills over to the US. You DO see some pills from europe on the East coast, but its increasingly rare.
As for the whole meth/amp thing....well its kinda like why some people eat rice and others eat potatoes....because thats whats there. crazy hicks started makin it in the US and its exploded here....just never happened in europe.....but as others have mentioned, its creeping up there and you will see it expand in "popularity" over the next few years i would imagine.
its kinda funny how mexico gets all the shit here in the US for having drug runners and being our drug supplier when i bet you more drugs come in from canada than from mexico.....well maybe except for shit brick weed. but the good weed and the pills, come from canada!
PS, prices in canada are less because that is the manufacturing point....no messy smuggling operations needed, therefore, cheaper!