That's the thing. Why couldn't Bioware titles achieve the sales numbers of Fallout 3? Or a Skyrim (which sold 7 million copies on it's first week and has sold 30 million by 2016)? Hell, even CD Projekt Red's The Witcher 3 managed to sell 30 million copies as of 2021.BioWare games sold rather well, ME2 for example sold 5m, DA2 only like 2m from what I've read. Bethesda games were huge and had legs, with Fallout 3 selling over 12m copies. It looks like their open world formula was more popular than the more story driven approach by BioWare.
For some reason Bioware couldn't achieve the same sales numbers as that of it's competitors despite the hype surrounding their titles and the backing of EA.