The retiree economy will be a much bigger challenge to Bitcoin than to Monero. Especially in a world where retirees will be the last to adopt Bitcoin as money. They prefer what they used their whole life. Fiat.

Which means they will convert their investments back to fiat to pay for their stuff.

Meanwhile Monero is not an investment. It is used for payments. What made it unattractive in the past as an investment ironically may lead to it becoming the best investments of the coming decades.