This has always felt a little unintuitive to me, because you'd think that after seven decades of practice at warping reality to make itself feel good, Trump's brain would be able to handle something as straightforward as "blame his loss on a conspiracy". I always expected him to get over it much faster than expected. Not in terms of being a gracious loser, but by abandoning the Presidency altogether the moment he lost and never mentioning it again.
I mean come on, you or I could've come up with that narrative and we're not even deranged lunatics. Trump's mind is like the ending of "2001: A Space Odyssey" when it comes to making excuses for its own failings.