lack of underlying fundamentals (like company profits or assets)
The underlying fundamentals of Bitcoin was the ASICs and electricity cost, it doesn't produce for free or low cost.
The ETF version was no underlying fundamentals, they didn't spend anything, instead they only claim if they have the coins.
Bitcoin is already too big to fail, I'm sure in our generation, Bitcoin will keep exist and the demand keep increasing since it's the only one cryptocurrency who has the unique utility.