To be fair, I’m not sure if “just arrest anyone convenient and frame them”, is entirely in the wealthy’s interest here. Making an example is one thing, sure, but if you do that and dont get the guy that actually did it, then you have a guy out there who has proven themselves willing to go out and assassinate CEOs, who may well decide to do it again. If you do have the means to catch that guy, then what motivation is there to not just send him through the court system rather than framing someone else? Less risk of a frame up being discovered and sparking even more resentment if you have at least some genuine evidence, after all.
To be fair on them (not that there’s much reason to give them that courtesy), most of the Trump supporters I encounter at my work and such seem to truly believe that a sizable majority of people in the country agrees with them and that everyone else is either some kind of hostile elite or a crazy fringe. If they really do believe something like that, then this is kinda self-consistent of them, since they would therefore believe that they cant lose a fair election, and therefore that them losing is evidence of cheating even if they don’t have clear evidence of how, but them winning would be evidence that, if there is any, it at least isn’t enough to change the outcome.