The premise here is flawed for two reasons:
1. The OP suggests Origins was released on PC first; it was not. It may have been inferior on consoles and I believe the PC version doesn't allow you to use a controller (Steam says no controller support, but I swear I did it - I probably used a mod or script to do it) because I remember fussing with that a lot when I bought a second version for PC to use some mods. But DA:O was released same day on all platforms, except Mac OS, which came later.
2. What people really mean is "keyboard vs. controller." I play games on all systems, and I'm happy enough to play games on my PC, but I do so with a controller. I know many people who play PC only (because it's what they have - we happen to have everything in the house) but favor the controller. There are plenty of PC gamers who either don't mind or prefer controllers. They aren't the loudest maybe (though this view is plenty loud when someone points out the ease of controllers as a benefit for consoles, saying they can do that too on their PC), but they are definitely there. IRL, I don't know a PC gamer who doesn't own a controller that they have plugged into their PC. I know maybe one that deeply prefers the Keyboard, a few that deeply prefer controller like me, and many that don't have a native preference and just play whatever seems better for the game.
Now #1 is a minor flaw, but #2 is a major flaw in reasoning. Yes, the issue is money, and showing initial PC sales are undereported doesn't counter the argument (despite the fact being true). Because of #2, even most people on PC won't be impacted heavily by the controller UI and control schemes being favored. Less people are impacted this way than if the keyboard UI and control schemes are favored. In a perfect world, both would be amazing, but if one has to be favored, it makes sense that it be the one that A) everyone has an option to use, and b] most people will be willing to use.
Granted, they're going to tweak it and fix it for the Keyboard folks, it looks like, and it's good they are. (There are also lots of players I've seen reporting that the Keyboard controls maybe took getting used to but are fine.) But the fact that this would come in a patch rather than at release doesn't surprise me. They are designing first and foremost for the majority, and the majority fall into the group of "Can use a controller." The majority will never fall into the group of "Can use keyboard" unless it is a PC-only release; even then, a lot of games develop controller support now because many PC gamers want it.
I think BioWare's big mistake was saying they had spent a lot of time on making it right for PC, which made people expect a lot of attention to Keyboard, reasonably, and PC UI. Actually, it was one of the reasons I didn't buy this game on PC (PS4 instead) because I was worried the PC version would lack optimized controller UI. People naturally thought it would be like Origins, which favored the Keyboard (and did so in a time when it was mildly reasonable for an WRPG to do that, but times have changed and the market for RPGs has widened, and the way people have set up their PCs in their homes has evolved from desk to living room, in many, many cases).