Spreads compress when rates are low, so yes, loans are less profitable per dollar when rates are low. But many more people and companies want to borrow so banks

Spreads compress when rates are low, so yes, loans are less profitable per dollar when rates are low. But many more people and companies want to borrow so banks make out fine. And there are plenty of other financing sources available for companies, including issuing equity, VCs, junk bonds, which grow in popularity when investors need to chase yields.