The problem to me seems to be that the two 'eras' never meet. Now I don't know all the ins and outs of the business but I realise most guest spots have to be paid for.
Take for instance the forthcoming Alice / Bon Jovi tours in the UK. We all wait with baited breath expecting the support slots to be like the old days i.e. quality hard rock, and they're crap. Someone needs to take a chance and mix the best of the old with the best of the new but no-one's willing to foot the bill. The old band shows currently touring the States would be livened up significantly with the likes of Damned Nation or Push on the bill.