Dimebag Darrell's estate was worth $700,000 when he passed. Pantera sold around 15 million albums worldwide not to mention their DVDs, merch, etc.
Slayer has sold around 10 million albums worldwide. Their DVD sales are ok & there merch sales are good for a band of their stature.
$700,000.00 is alot of $. However, I don't see a person who spends $ like a rockstar or has bills like they probably have being able to retire at age 50 and live comfortably for the next 20 years. It's good $ but that is 20 years worth of taxes, bills, upkeep on houses/vehicles, health insurance combined with there band not touring, royalities shrinking, merch not selling as well due to the band being out of the public eye, etc.
And I don't believe any one member of Slayer has made as much $ as Dime did. Those guys could retire at age 60 on that if they lived to be 75. Not at age 50 though.