The key is in the primaries, it’s where the money and the “party faithful” of the machine people (both parties) nominate their handpicked candidates.
Until us conservative minded folk put the bulk of our efforts into primaries the oligarchy will get their preferred candidate in the race near every time, and they have one from each party (i.e. it matters not a whit to them who wins the actual election because they have both sides of it sewed up in the primaries).
If you don’t field right minded candidates and vote in primaries you’ve already ceded the field.
Good point about primaries. We tend to snooze then and then lose later...