As always very good information friend @spectrumecons. I would like to take the first option you offer to qualify, that of "Auto Compact", and mention something very special that occurs in my country Venezuela, in which it is very well known internationally that there are many deviations in the economy, Most of them are the product of the entry barriers that you explain, which are set by the government forming a monopoly.
This occurs in many areas, one of them is in a brand of compact cars (not all we have). In my opinion this industry could normally be classified as a monopolistic structure, but in Venezuela NO.
The entry barriers placed by the government (mostly with political funds) for the acquisition of these vehicles make them have an exclusive monopoly of them.
RE: Market Structure #1 - Introduction