Would you use Bitcoin as a means of payment when using cash dollars allows you to maintain complete confidentiality, avoid volatility, pay no commission fees, avoid technical barriers, and pay anywhere in El Salvador? I think I would choose to use cash dollars. Most Salvadorans do the same because it is safer and more convenient. The Salvadoran authorities have given their citizens the opportunity to use Bitcoin. If someone does not want to use Bitcoin for payments for some reason, that is their choice. But I don't think El Salvador's ideas have failed. They are simply still in the early stages of adopting Bitcoin, and El Salvador's investment program only shows citizens that the government fully trusts Bitcoin not only as a store of value but also as a technology.
Well, cash's convenience won't last for long. The plan is to phase out coins and paper money in favor of government-backed digital Fiat currencies (either stablecoins or CBDCs). Once people realize their privacy and freedom is at stake, they will switch to Bitcoin. Even if BTC is a pseudonymous cryptocurrency. With CoinJoin and even privacy-focused L2s (like Ark), it will be possible to use Bitcoin as cash. The Lightning Network (although flawed) already provides low fees and near-instant settlement times. Volatile market prices remain the only obstacle for BTC's use as a currency worldwide.
Maybe if the world becomes "hyperbitcoinized", things will change? Only if Fiat is no longer relevant. You and I know there's a slight chance this will happen, so BTC will remain a store of value forever.