The point about pre-approval is tremendously important. Elections are a two-step process, nominations+vote. The fact that the first step is controlled by a small elite of party apparatchiks and the rich and influent is ENORMOUSLY important and very underappreciated. By the time citizens go to the polls, opaque party politics have already picked a handful of candidates (at best) for the public to choose from.

A nice quote about this, from a corrupt 19th-century NY politician and businessman: "I don't care who does the electing, so long as I get to do the nominating"

Very nice speaker about this: https://yewtu.be/watch?v=PJy8vTu66tE