Of course n can be smaller and the specific people less trustworthy, but that's quite a different thing.
With decentralised money, you get the safety of a globally distributed attestation backed by cryptography without a single authority controlling the supply of money or your funds.
There is no halfway option. You either have a single authority that can exercise control or you do not; number of delegates for exercise of control is almost irrelevant since you can change banks.
FDIC deposit insurance does not protect against losses due to theft or fraud, which are addressed by other laws.
That's covered by private bankers bond insurance, much like you could get for a decentralized stored pots of gold or you can buy insurance in the form of put options (like on IBIT) on the loss of value of bitcoin or if your cold wallet is stolen you can initiate legal proceedings against the thief.[] https://www.fdic.gov/news/fact-sheets/crypto-fact-sheet-7-28...
I guess Hollywood has mislead us yet again in pretty much every bank robbery scene with dialog like "Nobody panic. We're not stealing your money, we are stealing the bank's money".