There is no reason that the third-party cant be a contract with globally accessible permissionless apis, that let you borrow peer2peer or peer2protocol against your assets, and that upon you not repaying your debt liquidates your position (by other people/protocols bidding for the assets that are out of position, usually over-collateralized at 150% min).
Most of defi is structured in this way and it is working fine, it works because it IS being integrated and made compatible with existing finance.
This is "futuristic" because anyone in the world has opportunity to lend/borrow to anyone else in the world, to write code that automates savings accounts by rotating these positions, to write business logic of their startup to borrow money when they need and pay it back when its the best time for them - scaling their finance on demand like spinning up an ec2 instance.
A system where you have more voice and opportunity for your work/savings/co-op/club, compared with whatever the state of banking is in wherever you happen to be born in the world.
Concrete example: I asked my bank to borrow some money and showed them my bitcoin, they predictably said no because their system cant handle it. I wrapped it onto ethereum, deposited it in aave, borrowed usdc, withdrew to my bank account and carried on with my life without needing the banks permissions. The people lending that usdc to aave to lend out to me know it is safe and I cant run off never paying back my debts and interest (otherwise they get my over-collateralized btc).
permissionless global p2p lending and borrowing. it isn't futuristic, it is the present. ill never understand why "hacker"news doesnt find that amazing.