Yanis was talking of lending.
Lending in Bitcoin can happen in two ways: the first is through imaginary Bitcoin (“borrowed from future installments”) in a layer 2, which is what he was describing, although I agree that, unless the government mandates accepting money from that layer, it is hard to make it systemically used.
The second one is to only lend coins that you have. In a deflationary monetary policy, lending is strongly disincentivized, as it would need to beat both the rate you would gain from the value of your coins increasing, and the default risk.
Much of monetary policy is about finding a balance where financial institutions will be incentivized to lend despite the risk (which is already a hard sell even under inflation!) without nudging prices.
It is plausible that a Bitcoin economy in stablestate (once coinbase transactions are no longer) would have very little lending. Is it outside of the realm of possibilities that, in such a world, innovation may decrease, and legacy becomes a more relevant factor for wealth?