Sounds like btc is good for large amount of transfer as relatively low cost but not really ready for day to day expenses like gas/grocery. Yes?
The idea that everyone will run custodial BTC/Lightning wallets is also rubbish. In the future, there will be institutions that do what banks do today: Give out accounts, which are non-custodial wallets like your todays online banking, and settle transfers with other banks in bulk by doing actual BTC onchain transactions.
Average Joe in 2040 will not run his own wallet but use an external service provider - just as Joe is not a member of the SWIFT transaction network, he will not be settling debt with BTC transactions but rather have an "account" and pay with whatever L2/L3 technology we will come up with.
It will be like in the gold-standard days. You had the right to exchange your paper dollars for gold, but no-one ever did. Yet every transaction was backend by gold, just as every L2/L3 transaction will be backed by bitcoin, though no onchain transaction will happen.
You could use something like Litecoin, Solana, maybe even Ethereum if you’re willing to pay the fee.
You can use bitcoin completely/as anonymously as cash if you wanted to, the same way you’d have to put in a bit of effort to have a completely anonymous cash transaction.
Monero (XMR) which is a fork of bitcoin, is much closer to actual cash
You can buy ETH, then you can use a TOR crypto exchange to swap it from ETH -> BTC into your wallet.
Just an idea though
There was a very contentious split many years ago now (Bitcoin Cash vs Core fork) regarding this point. Until then, it was taken for granted that block size would continue increasing in proportion to transaction volume in order to facilitate such use. This was Satoshi's expectation, and there was little-to-no discussion otherwise. Quite suddenly, a few powerful, well-positioned people (with conflicting interests in the form of their Lightning side-chain solution) conspired to form a consensus of limiting on-chain transaction bandwidth via astroturfing and comprehensive censorship.
Whether they were responsible visionaries with the foresight to avert disaster using a novel solution, or spiteful saboteurs driven by greed and power, is up to the reader. Un/fortunately, they were very successful.