Puny mobs, SIB and mission rewards.
Yes, it has gotten cheaper to play.
All the while MA also added ways of playing on a more expensive level. But that's not the point. No one is forced to play at that level. "High end" back in the days was pretty much killing atrox old alphas (used to be toughest one) and araneatrox. That's hardly high end today, and keep in mind an atrox stalker today is way stronger than an old alpha from way back.
Didn't think about mission rewards, SIB; so yes i guess EU has become less expensive in those terms.
Also smoothing of hunting loot returns means less turnover required to achieve decent return %.