Gold's utility value is such a small fraction of its reserve value, that it's moot. And gold has had 1000s of years to find an alternative utility. Even if we did, it's unlikely that that utility would be worth more than gold's market price. I.e. high prices deter utility (this applies to BTC too).

Bitcoin (or potentially Ethereum) in particular are a much more efficient reserve than gold; being a reserve unit doesn't require any physical characteristics, but security, pseudo anonymity, and portability can be significant driving features in adoption.

[Opinion and speculation alert:] It's clear at this point that Bitcoin's original currency goals are mostly lost, but Ethereum has a good chance of actually meeting them with ETH2. Bitcoin has become a significant reserve unit though, and it's energy costs is the only major risk against it (hence a potential flight to ETH). Although people who invest billions (including indirect investors via ETFs) don't particularly seem to care. Other specific-utility cryptos might also succeed, though I expect most of them to be built on top of ETH.