Yes you have to take times into account but DA was 2009, NWN2 was 2007. Also I'm trying to compare apples to apples, but lets look at something like Diablo 2 at 30m sold, this is more action cRPG. The point here is Oblivion was 1% of the population, if we add European Canadian, and US population, because they would be the primary group playing at the time. about 1B people. That is still obscure. You can find 1 in 100 people to talk to about it. With Diablo I could find 1 out of 33.
You also have to keep in mind, it is not JUST rulesets or how specific mechanics work that sell a game. If a game is bad, it will not sell well regardless of the ruleset. If a game is good, it will sell well. DA:O sold well (Asdie from brand recognition) because it was just a good game. It played well, was written well and it had good reviews. NWN2 was kind of.. uh.. bad. Not greatly written, it looked worse than nwn1 (and much worse than DA:O imo) and had poor controls. It was a huge dissapointment after nwn1.`Looking at Dragonage2, same idea. It was not received well and considered a bad game compared to DA:O.
Diablo2 was a very solid game, it was fun playing it and good reviews too. That all does help with sales, too. And Blizzard had the brand recognition to help too. This all goes beyond just rulesets.
I get it, but why hasn't the ruleset had a breakout game? Inquisition sold well. Even tho DA2 did somewhat flop it still held onto the numbers DAO had, I cant seem to get solid numbers, but it looks like 2.5m. So it went 3.2m, 2.5m, then 6m. I still liked NWN2, but it fell short when compared to NWN for sure. I believe I said it in a previous post but I think NWN is the best of all time. The storyline was great, and I loved Deekin. It was so good, it switched my fascination from Minotaurs to Kobolds, for monster races. NWN2 and sorry if I am misremembering was a different story, and not a continuation, which disappointed me from the start. Then you meet Deekin in the game, but hes a merchant now, and he isnt available as a companion. This might be a Mandella effect or false memories but that's how I remember it. NWN2 did bring the concept of playing D&D on the PC platform to life, I think, again I'm going off of human memory here, so I might be assigning false values. The problem was it still took too long to setup things, and so it was easier to stay at the table, for that sort of thing.
3E/3.5 also gets a lot of crap too, but it fleshed out a lot of the lore for D&D that 2E just never did. I might be biased because that's more of what I personally grew up with, AD&D/2E was on the way out as I came into it. It did however, expand the universe a lot, even though the mechanics may have still left something to be desired, and it brought an ability to customize your character more. I don't think Multi-classing was really a thing in 2E either, or if you did it wasn't all that great cuz things didn't synergize well.
