2040?!?!? What planet is he on? Cryptos move at multiples the speed of "normal" stuff. USD will be gone much sooner. By 2040, gold will of course still be around, USD along with most other national currencies i.e. the nations of the US allies, will be replaced with a globally sanctioned and controlled cryptocurrency - prob within 10 years or whenever the next major economic crash happens, which doesn't seem too far away.
Bitcoin by 2040 will probably be dead or relegated to collectable/antique status as other more useful cryptos fill other niches and the global cryptocurrency will be used for standard payments and transactions.