Interesting point, and eventually things may move that way. It may become as transparent to the users as changing channels on the radio. But for now we're still at the stage where there isn't enough device cross-talk to afford us the luxury to do away with meaningful / memorable domain names (much like how many new radios still need to be tuned in to our preferred stations). We print website addresses and place a great significant on the address bar - so it makes sense that a domain name should fit the product.

While QR codes, mobile apps and search engines are mitigating the need for domain names - I don't think we're quite there yet.