Bitcoin attempted to replace cash, but failed because the transaction costs are orders of magnitude too high. The high cost of zero-trust makes it a desirable medium of exchange only for criminals and scammers.
In an effort to make Bitcoin a reasonable medium of exchange, various businesses arose to act as intermediaries/market makers. But this violates the trust-free model – and many of those intermediaries have proven to be outright scams. It turns out that trusting an intermediary to handle your cryptographically untraceable asset is not a wise thing to do.
So that leaves Bitcoin in a similar category as gold. You're either a paranoid type for whom the high cost of holding and transacting the asset is a price you're willing to pay for an asset that could survive a global meltdown. OR you extend trust to various intermediaries (gold ETFs, bitcoin ETFs for example) and treat it as just another tradable financial asset.
Bitcoin is undeniably the cleverest way anyone ever became a billionaire. Nakamoto's sole contribution was posting an anonymous 9 page whitepaper to the internet and voila, today he (or she, or it) is worth $80+ billion.