"Could"? We're already in a bubble. Most notably, the Bitcoin price rally coincides with Tether printing out $10B of their "stablecoin", fully backed with what very much appears to be nothing at all.

Here's a primer from HN's very own patio11, from back in late 2019 when they had only printed $4B: https://www.kalzumeus.com/2019/10/28/tether-and-bitfinex/