Oh, they did learn. They did.
And what they learned was if you frustrate players enough with terrible droprates of all the good stuff in your RNG store, some of those players will start throwing money at them to get BioWare points/Platinum and just hope that if you fling enough excrements at the wall, some of it is gonna stick and get you the drop you want.
Of course, everyone is still frustrated, but BioWare/EA gets money and that's what they want; plus they can placate everyone that flinging sh- err, microtransactions help fund the free MP DLCs (of course we don't know exactly how much of those microtransactions directly go towards funding such DLC, but why should we know that, right? Right?), so in the end they even get some positive reputation for it.
It worked perfectly in ME3MP. So why shouldn't it work here?
I know the 'perfectly' is just you being extremely sarcastic, but at least it worked far better in ME3MP.
There was no crafting system in place for ME3, instead we got a leveling system with our weapons and gear and the consumables were primarily powers they didn't want people having such as cryo ammo. This meant you could at least acquire the same weapon (screw that Highland Dirk) enough times that it would at least be useful in some difficulty or another, in DAIMP however the same item was just salvaged for parts that were worth less than the whole product thus making it more likely that you'd get that same piece of junk over and over. The crappy weapons of ME3MP eventually ceased for consumables which meant you'd eventually cap consumables and get a better item that way, that's how I got quite a few URs way back when I was still playing. My consumables in that game are now almost non-existent however.
The other thing that ME3MP had over DAIMP in terms of RNG was the Character cards, they were useful cosmetically for the first five (four in some cases) as they allowed color, patterns, lighting color and a small series of other non- functional cosmetic rewards to be applied to your heroes as you went on. These cards were also dual purpose in nature as they gave you an experience boost depending on the level of chest they were acquired from so you had a far easier time leveling and promoting your characters. This meant even acquiring the same character card over and over had a purpose as you were still gaining a stack of exp for seeing that stupid Human Adept card for the 700th time. I would have actually paid for better armor customization in DAIMP as the lackluster nature of the gear we got was terrifyingly bad.
Third the gear options were more than % to this ability's cooldown or damage, my personal favorite was the Batarian Bro-fist. I would have liked to have seen a ring, belt or necklace that allowed my archer to be a Bow Fencer and use his bow in melee range when someone was closer to him, because honestly who doesn't want to see Hall or Thornton be the Green Arrow when people try to stab them?
https://youtu.be/egrVl7yWtYg?t=1m25s