A trip down the internet rabbit hole led me to the wikipedia entry for Bette Nesmith Graham, mother of Michael Nesmith of The Monkees, and the inventor of Liquid Paper, aka White Out. She sold to Gillette in 1979 for just under $48M USD, which would be something like $175M in today's money. Bette has since passed (as has Michael, for that matter), but White Out has become all but obsolete: I can't imagine that it still pulls in more than five digits annually in sales. Which led me to wonder, how many people do you reckon are still alive who got rich by selling something that no longer makes money? Like, what's it gotta be like to be the grandchildren of whoever invented 8-track tapes, and you can't even brag to your friends about it, because all your friends are like, "Dude, WTF is an 8-track tape?"