You're right, monopolies certainly don't drive progress. But the possibility of a monopoly can.

Progress requires R&D, and R&D is expensive and unpredictable. No one would want to do the type of long-term research that invigorates the economy or even creates brand new industries if they won't take in the lion's share of the profits. So it would be a bad idea to implement a policy of breaking up any and all monopolies, despite the fact that it is better in the moment (similar to Newcomb's problem). In fact, we actually institute monopolies using government power, via intellectual property.