Hmm...I don't recall anyone suggesting a complete shift for the MC. I believe the initial suggestion followed my argument, which is it could draw in extra players if it were an *option*. Perhaps a toggle when beginning your game, or an optional side quest to acquire breasts somehow. If integrated this way it wouldn't alienate anyone.
Then you fall under the counterargument that's already been provided: dev time is a scarce resource and implementing this option would subtract time from getting new content for those that don't care about it.
If the team behind the game was bigger, sure, it could be reasonable. But it's not. Introducing this option, which interests an audience different from the core audience the game has been tailored to, would dissatisfy the core audience and would thus be hazardous because you never know how much of a new audience such a change would get you.
Not every game is meant to satisfy every sexual preference. One should just deal with it.
Some of the requests people make in this thread are on the same level of asking a furry game developer to add the option to be a human. Would it be possible? Sure. Would it take time just to realize scene variants whilst everyone else gets no new furry content? Yes, a lot.