When you deposit money in a US regulated bank, there are basically two places that can end up:
- on deposit at the Fed, in the account of a Fed member bank (which could be your bank, or a bank your bank has an account at)
- loaned out by your bank (or again, a bank your bank uses)
The Fed, so far, has refused to allow new member banks (eg that could deposit at the Fed) that don't intend to ever loan out deposits. They would take all customer deposits and stick them at the Fed. Many (most? the ones at the Fed anyway) think allowing this would siphon away money that would otherwise be used to make loans. They are, in effect, putting their finger on the scale to push you to allow your savings to be used as loans.
The rise of Private Credit, where wealthy individuals and institutions loan money to private firms for to fund loans is the new thing that could break this open. These arrangements are long term, the customer can't "call" the money back, they are committed, and (for the most part) their commitment matches the duration of the loans. So there can be no bank runs. And the people providing the money know what they are doing.
Levine is mostly arguing that with so much money in private credit, we could do without forcing small savers to fund loans.