LOL, Trump is doing what Trump does: double down.

Probably. But let's not completely discount the possibility that this was Wiles' decision, or a mutual decision, or somewhat mutual.

Chief of Staff is an insane job, and the average tenure in the position is between 1.5 and 2 years. They very rarely last a full term, even when there's no substantive reason for them to leave. It just chews people up.

After the midterms, and especially after a bad midterm, the WH will almost always take inventory of what the senior officials' plans are. They ask everyone whether they're planning on sticking out for a while or leaving soon, so that they can more effectively manage transitions. So while it's certainly possible, maybe likely, that Wiles was pushed out because of the midterms, it's entirely possible that she wasn't going to be sticking around for much longer anyway and this just moved up the timing.

I'll admit, Miller seems like a b@tsh!t insane choice for the role. Except....who else? There's probably a very short list of people that have the capacity to do that job (even badly) but would be willing to do it for the last two years of a Trump Presidency when the Democrats have unified control of Congress after a brutal midterm. Trump paid some lip service to working with Congress, but it's more likely to be a running knife fight for the next 24 months. Miller almost certainly doesn't have the chops of Wiles, but he is at least going to be 100% brutal and unsparing in his dealings with Congress. Which is probably what Trump needs, rather than anyone who might be considering what their post-Trump political life looks like....