I agree that they both hold onto their monopolies. But I don't think it's because they "destroy competition". Take Bing for example: it is quite alive. Google just delivers better search results. Yes the results have been deteriorating, but every time I get frustrated with them and try Bing as standard search engine, I switch back after a week. I don't like the google monopoly, but their core product is still not being challenging by anything I know of.