no classic rock is not overated. It was an age of pioneering new sounds,and not being scared to break new bounderies. Classic rck is a ver diverse world of sounds. Yeah there is great bands today, great artists. Some of which is very original and innovative, but still lacks the ability to have a presence on people that classic did. Most Modern rock sounds the same though. In the age of commercialism and cooperate rock, many bands and artists scurry to latch on to the present trend or tend to copy popular music. Again this isnt becaus of lack of talent out there,but because of the death of record companies.
The thing is though, a lot of old bands were just as commercial, if not MORE so, as many bands we have today. Tool and APC, for example, are much less commercialized than say, the Stones were. You have to remember that for the twenty or so true classics that people think of when you say "classic rock", there were thousands of shitty bands that everyone's since forgotten.
And modern rock does NOT all sound the same. Sure there's plenty of crap that does all sound the same, but there are also a good number of incredibly talented musicians who have a sound all their own. Just like you can instantly recognize a Who song, you can also instantly recognize a System of a Down or RATM song... It's really not much different now than it was then.