While I see the argument, Pay-to-win loses some of its teeth in a cooperative environment. You're not really competing against anyone in the same way you would in a pvp setting. One might counter that Prestige is a form of competition, but let's be honest: many of the folks in the Top 100 right now have likely glitched their way there. So "braggin' rights" are all but rendered pointless.
On the other hand, BioWare and EA are indeed in this to make money. They have a fairly simple operating paradigm: keep players just frustrated enough to continue grinding without making them so frustrated they give up. They toss you a bone from time to time, make you hopeful. But they also want to keep the pressure on, because many (most?) folks make poor decisions when they're frustrated. It's likely what fuels a good chunk of their Platinum sales. You can either mindlessly grind for gear and gold for weeks or months, or you can throw $50 at a time at them for Plat and open a metric foktunne of chests. Guess which they're hoping you do?
Selling best-in-game gear circumvents their philosophy. Why sell you a Hakkon weapon for $10 when they can try to entice folks who really want one bad to buy a bunch of plat for far more money? They're counting on human greed and impatience to convince folks to part with their cash.
It's truly ingenious when you think about it. Manipulative and borderline evil, to be certain. But ingenious nonetheless. 