Monopoly (alternatively oligopoly/cartel) is the entire issue, all the time.
Who has a monopoly...they're doing bad stuff.
Who has to compete for customers? They're doing good stuff.
Does the government have substantial power? Folks are trying to use it to gain monopoly.
Protectionism: 99.8% of the time...it's group A saying: group A's products are necessary for future growth. Therefore we should create a local monopoly (or otherwise uneven playing field) and make everyone else in the group pay more for A's products.
Regulation: 99.98% of the time...it's group A saying: let's make sure the legislation gets written in such a way that favors us existing players, and discourages new entrants.
The power to create monopoly is VERY bad. Presumptively, anything that is an attempt at monopoly-creation should be opposed on principle. It screws everyone else.