Not op but I also agree with the framing assuming you add “and they provide a vital service” to both. If a vital service is being used to extract profits it should be regulated so that equal access to the vital service can be provided. If a vital service is being provided but cannot make money it should be regulated so that it can be sustained since it is vital.

Now what is vital? Is Spirit vital? That’s the hard to define part.

Breaking down complex topics into binary black and white doesnt have to be wrong. The more important part is, how much wealth they extracted and how exactly. Was it market dominance with a superior product or amoral cost externalization.

The angle of treating transportation as regulated utility shifts the business focus away from profit onto providing services, which sometimes can cost more than your income. Similarly, would you close schools, because they didnt make enough money? Airlines are highly subsidized anyway, treating them as regulated utilities falls short of taking public ownership as public institutions, where services just cost money/subsidies.

The extremes of capitalism have a negative impact on people’s lives.

The first scenario it harms us by under-serving and scammy practices, the second scenario it’s over-extractive and funneling money from the many to the few.

Companies like John-Deere should be able to survive without abusing their downstream customers. Many farmers are importing tractors from China because they're cheap and not hostile to repair like JD is. Some people might call it a "smart business model" to sell interdependent services, but in the long-term it's suicide.

Whether or not you solve this through regulation, that's up to you.