I'd believe that necessary primitives are out there, but it's not really enough to have a solution in theory. A crypto project will have to stop such things in practice before they can legitimately claim to have obsoleted the banks.
If your intent is to lock funds for a specific number of blocks or a timestamp/block height you don't need more than these primitives (nLockTime, nSequenc, CLTV or CSV)... the first two are fields in any Bitcoin transactions, the others are scripting instructions. Some wallets allow to use these various flavors, from memory, both Bitcoin Core and Electrum offer some of these timelocks through their UI.
The point was not that this alone would make bank obsolete, but rather that this isn't just something "new" cryptocurrencies feature.
Bitcoin literally has timelockS (multiple kinds) built-in in its scripting since its first release...