My counter to that would be if people feel that strongly they would be buying the games regardless of quality just to make a point. Why would a publisher bother taking a risk when Ubisoft just proved you can roll out a protagonist like Aiden Pearce and top the charts anyway?
These are games which NEED to sell millions just to break even.
So video game developers should stick with doing what's proven to work? If that's the case why are you only applying this to the game's protagonist? If the best selling game is a shooter, shouldn't all games be shooters? Why risk trying another genre? Why not just copy the mechanics and design of the current best selling game? Probably because people eventually get sick of playing the same thing over and over and start looking for something different. A lot of the best-selling games in history were games that took a risk and broke the mold.
Now I would argue that the gender of a game's protagonist is a lot less important to a player than game mechanics, and if that's the case then how is changing it a huge risk? If you do think it's a huge risk then I ask again why is it fine to take risks on changing mechanics/setting/everything else but it's not okay to take a risk on the protagonist?
Now the reason I believe it's beneficial to have and show a female protagonist is simple. According to ESA reports the percentage of women gamers has steadily been rising. Even if this is just mobile games or online games that doesn't change the fact that more women are paying attention to video games. My mom used to scoff at my love for video games and never understood why I played, but recently shes started playing app games on her phone and loving it. She still doesn't play console/PC games but now when she sees me playing she actually comes to see what's going on and asks about them. I know that's anecdotal but in my experience games aren't such a weird hobby anymore, so previously untapped markets are paying more attention instead of immediately being dismissive.
So anyways, since more women are paying attention I think the best way to pull them in is to feature interesting, non-sexualized female protagonists. The video game industry already has the male demographic and I don't see any evidence to suggest a female protagonist (or at least a choice of gender) will dissuade them from playing if the game is otherwise good. You mention female-led games failing more often but there's such a small sample size that I see no reason to take it as definitive. I see little risk to the male demographic by promoting a female protagonist but there is a chance to pull in a mostly untapped market, especially for a game that already has an established tradition of being able to choose your protagonist's gender. Marketing should be aimed at people who don't already play Dragon Age games, not to people who are already likely to know about them.
Honestly I think the biggest reason for the dominance of male protagonists is that for the entire history of video games, the vast majority of game developers have been male. Making a male character is probably much more within their comfort zone than making a female. This isn't because women don't like making video games but because technology has always been a "male" pursuit. Boys are encouraged to become inventors, astronauts, engineers, etc. while girls have historically been discouraged from those paths. I think this is also a large part of why more boys generally play video games than girls. I know I probably wouldn't have gotten into video games as a child if I didn't have a brother near my age. My parents bought the NES for him, not for me, but I always insisted on playing with his toys.
Anyways I don't remember if this has already been posted but there's an interesting article here that talks about the history of video games and how women have been excluded.