A figure I have recently stumbled upon suggests that about 7% of the world population will, or have, had appendicitis in their lifetime. Cutting out the appendix was impossible until very recently. Even if the appendix only just started, in evolutionary terms, being infectable, it would still be capable of wiping out an entire population in no time at all, meaning some other population would adopt an alternative. No matter what the benefits, the costs would be detrimental and most definitely outweigh the former. We've had at least a million years (correct me here if I'm wrong) to get rid of the appendix, but we didn't, even though it kept on killing. It seems very counterintuitive that it's still here. Can anyone explain, please?
Edit: I recognise that an appendix serves some purpose to the body. My question is: aren't the benefits much less significant than the costs?