Was thinking about this yesterday.
The current banking model is set up so that small amounts of money can be self custodial (cash) but large amounts of money must be held at a trusted institution for safe keeping.
The Bitcoin model is the exact opposite. Large amounts of value are worth taking self custody of and paying for the use of block space, while small amounts can be kept with a custodian for better payments solutions. Lightning will scale much further, but in the future you could have an on-chain address which represents your life savings, one single lightning channel going to a trusted payments provider, and some small amount of remote liquidity to make payments through them. That’s all you’d need to live on a complete Bitcoin standard, and even without further scaling (which there will be lots of) we could service a huge proportion of the world through this model.