With my traffic...hardcore always has outsold softcore since the 90's when I started. To me it's a no-brainer. Do I want to pay to see a cute girl prance in her underwear, masturbate, and occassionally eat another girl out...or do I want to pay the same money to see a girl do all of those things PLUS fuck. It's an apples to oranges comparison for sure, but at the same time I see it as you can either buy a real nice car for x amount of dollars OR you can buy the same model car with all the bells and whistles for that very same price.
There are always exceptions of course. Some softcore girls have had great careers. And of course there is a niche for guys who don't like to see a girl getting fucked. (hell, there's a niche for everything)
But for me personally, since my tgps have always had both softcore and hardcore galleries side by side...hardcore wins everytime. I suppose that if you had a freesite of some sort that featured only softcore then you could be a bit more successful with it.