Well, flat cymbals aren't the problem alone. That contributes to breakage of crashes when the angle of the sticks at the striking point of the motion are... uh, too... dang, can't find the words. You should crash with the shoulder of the stick striking the edge, but not too far away from "flat". Obviously they can't be perfectly flat 'cause then the tips would be hitting the top of the cymbal... In other words, if the crashes are flat and/or high, relative to your height when seated behind the kit, and you're kinda chopping toward the edges of the cymbals rather than coming downward on the edges, that's gonna eat up cymbals AND sticks. If you're really tall and can still come down from over the cymbals when you strike them, then flat/high isn't a problem.Thanks guys great info here. After looking at these posts I see that my cymbals are mounted too flat. I am hitting too hard and really for no reason other than I'm watching too many rock videos. Lesson learned. Expensive one at that lol.
You also don't want to adjust your motion to conform to how you mount your crashes. (Or anything else on the kit, for that matter.) You want to do the opposite. Find out where your comfortable motion to hit the crashes is, and put the cymbals in a position where they're comfortable to hit properly.
All that said, if you're bashing like you're in a metal band video, yeah, you're probably just hitting them too hard. The previous advice regarding that is also accurate, just thought I'd address that flat-position thing.