The most obvious is the technology--bikes, electronics, lights, clothing, protective gear (helmets). But I think attitudes have changed as well. I am hearing more and more politicians and city planning experts, as well as environmentalists and the like talk about cycling infrastructure, like it's the future of the livable city. I don't think people talked about this back in the 70's and 80's. The impending catastrophic doom of global warming might have something to do with the shift in attitude.