What is the difference between monarchy and autocracy as indicated in SB 4.13.11 purport?

SB 4.13.11:

For this reason the ministers and all the elderly members of the family thought Utkala to be without intelligence and, in fact, mad. Thus his younger brother, named Vatsara, the son of Bhrami, was elevated to the royal throne, and he became king of the world.
PURPORT
It appears that although there was monarchy, it was not at all an autocracy. There were senior family members and ministers who could make changes and elect the proper person to the throne, although the throne could be occupied only by the royal family. In modern days also, wherever there is monarchy, sometimes the ministers and elderly members of the family select one member from the royal family to occupy the throne in preference to another.