Last nights Antiques Roadshow, ( a repeat), had someone on who had a hat that was Michael Jacksons. The programme was made not long after his death and the hat was valued at over £25000. That was only the case because of his recent death, and it always helps the artist in terms of record sales. Though not really that much help if they are dead.
I think it would be better if they didn't die though, then we wouldn't have put up with the rubbish from todays useless crop. But I agree, those that carry on, end up being a bit of a parody of their former selves, and though they try to make new stuff, fans always want to listen to them at their prime.