This is honestly the biggest problem with gaming IMO. There has never once been a popular, mainstream game without combat.
There are games where you can not kill anyone, but violence is still the or part of the core gameplay mechanic. That's why I give props to Journey, and other thatgamecompany's games, it's a perfect example of a game that can be fun, without any violence whatsoever, and provide that feeling of satisfaction and immersion, that only gaming can offer. And a lot of puzzle games have violent traps and hazards, so you technically can't count those.
However, if you look at games without any violence in the past, they got either repetitive, or were abysmally short.
We need a pioneer, to break the gap and create a great, non-gruesome experience that no-one can shrug off as "boring" or "It's not really a game".