Lifter Failure

I've installed two summit K6903 cams and I never had issues I don't even rev them to 2000 rpm for 20 minutes either. I saw a guy badly overheat a chevy years ago revving a cam break in and I never have done it since. Ill go 1500 rpm etc. I will also admit I havent installed them recently, last one was 2008 one before was 2003. I agree on the convex lifters, also the cam lobe has to be machined to allow for the lifter rotation, the lobe has a slight incline so to speak. Cam lobe can be checked with a vernier caliper.