Earlier quoted context omitted.
Interesting, I never thought of antitrust as a scale, or that it should adapt to the state of the economy. I just thought monopolies are bad.
Monopolies are bad but "perfect competition only exists at the point of collapse" [1] A benevolent monopoly can be OK but both of the extremes of competition come with instability. [1] I put that in quotes because I thought it was a famous well-known quote but I can't find the original!
One of the things that works really well for this is to split monolithic national regulatory codes into less complicated region-specific ones.
California needs earthquake rules, Florida needs hurricane rules, Colorado needs altitude rules, etc. If you have one national code containing all the rules, you give the advantage to huge conglomerates that can navigate them all at the same time. A small company in Colorado has to comply with all the irrelevant rules covering earthquakes and hurricanes, which puts them out of business.
But if they each have only their own regulations, smaller companies can survive the ones in their home state -- and have more power there to address them if they're oppressive. So you get a different company in each region instead of one big national one. They put competitive pressure on each other because any who charged too much would make it worth it for one of the others to pay the regulatory cost of expanding into that region, but not so much pressure that everyone is locked in a price war and no one has any surplus to invest in the future.