That is a good point a lot of the big 70's rock bands won't be around much longer and you should rush out and see them if you still can. I saw page and plant in the 90's, not quite Zeppelin but almost. I also saw the who while Entwistle was there as well.
It's impossible to see every rock band out there play live .....but luckily we have DVDs, live CDs, live LPs that will accompany us for many a year and that for me, is all I need. Luckily again, I got to see quite a few important rock bands thru the years.