Not sure borrow at 9% to lend at 4.5% is that similar to bank business models...
BTC is 0.1% above 0.35 BTC. ETH is 0.25% above 5 ETH. I think we can agree these are not high rates.
On the flip side, the rates for stablecoins (GUSD, USDC, USDT) are quite high still, at 7.75%. But it's not impossible to imagine institutions borrowing stablecoins at higher rates than that.