This is not a serious question, but I think evolution has given them too much advantge by allowing them to fly as well. I mean they are bad enough without fying. Also do they get tired when flying, they don't do it very often.
Reminds me of a funny story. I went to spray a cockroach climbing on my kitchen cieling light. As soon as the spray hit it it took into the air, RIGHT at my face lol. I freaking jumped back yelling OH GOD like I was about to die. I don't mind most bugs that much, but something about cockroaches just scares the hell out of me lol.