From IFWiki

Monarchy appears in IF primarily as a standard element of the fantasy genre; historical, modern and sci-fi monarchies are vanishingly rare.

Standard Genre Element

Monarchy often appears as the default government system in heroic, lazy medieval or fairy tale fantasy. Neither explicitly advocated nor necessarily criticized, monarchy is here employed as an element of setting, to establish genre or to provide the player with plot impetus such as a quest.

Comedy and Satire

Incompetent or vicious monarchies form a conveniently uncontroversial target for comedy or political satire.