As a pure fiat currency Bitcoin has neither intrinsic value nor an invested community of users, which makes the value proposition very risky. If a cryptocurrency did start to become useful for mainstream use, everyone who isn’t heavily invested in Bitcoin would have a strong incentive to use something else where they could capture the profits which would otheraise go to the Bitcoin early adopters, and if that starts happening the floor for BTC is zero as everyone cuts their losses and moves on. Yeah, there’d be some HODLers trying to recruit users but that’d die off over time since nobody new would have that sunk cost.