Because they move away from the social optimum: it is possible to make everyone better off without making anyone worse off, in those cases.
More colloquially, monopolies are bad because they drive prices up, and firms with negative externalities are bad because they emit pollution which kills you.
Does that reduce to “economically bad is morally bad”?
Is it economically and morally correct to spend $(x>1)*n dollars to remove a negative externality of $n? (For example, an airport which covers runway repairs by adding a surcharge to fuel sales will result in pilots who buy a lot of fuel for long flights subsidizing pilots who make lots of short flights. But charging a landing fee will require hiring someone to collect the landing fee; the fuel is self-serve.)
If the monopoly had sufficiently high fixed costs and decreasing marginal costs such that it made the most money at a price that is lower than the equilibrium price of a duopoly, would it still be economically bad? Would it still be morally bad?
I’m confused: Why are monopolies and firms which project more than zero negative externalities morally bad?
Because they move away from the social optimum: it is possible to make everyone better off without making anyone worse off, in those cases.
More colloquially, monopolies are bad because they drive prices up, and firms with negative externalities are bad because they emit pollution which kills you.
Does that reduce to “economically bad is morally bad”?
Is it economically and morally correct to spend $(x>1)*n dollars to remove a negative externality of $n? (For example, an airport which covers runway repairs by adding a surcharge to fuel sales will result in pilots who buy a lot of fuel for long flights subsidizing pilots who make lots of short flights. But charging a landing fee will require hiring someone to collect the landing fee; the fuel is self-serve.)
If the monopoly had sufficiently high fixed costs and decreasing marginal costs such that it made the most money at a price that is lower than the equilibrium price of a duopoly, would it still be economically bad? Would it still be morally bad?