There is no 'Dead Head generation' - go to any GD-related shows and you'll see fans of all ages; new ones are being brought into the fold all the time. This will keep going for a long, long time, as it should.
Grateful Dead- Sotheby's Auction
Nearly 350 items including a bunch of their McIntosh amps up for auction-
https://www.sothebys.com/en/buy/auction/2021/from-the-vault-property-from-the-grateful-dead-and-frie...
https://www.sothebys.com/en/buy/auction/2021/from-the-vault-property-from-the-grateful-dead-and-frie...