Compared to 2016, 2024 had a *way* different feel. It used to be, normal people had a sense that there was a "uniparty" 0bama-McCain, 0bama-Romney, etc. In 2016, you could accuse Trump of a lot of things but the fact that Democrats and establishment neo-cons hated him gave Trump a sense of credibility. In 2016, Trump was offensive and even if you didn't agree with it, you could at least say it was funny. I don't think 2016 Trump was /ourguy/ but I do think he was a loose cannon and was in it for his ego.
Trump has no principles. He saw that playing the part of "America-loving conservative" was going to be easy when all your opponents are sackless dweebs and he nailed the part... and that's all it was, a part in Trump's ego-driven production. If Trump was 10 years younger and just now getting into politics, he could pull off the same stunt with the Democrats since they are in such disarray. Just tell them what they want to hear and don't be an evil witch like Hillary, a doofus like Biden, or a cackling hyena like Harris, maybe lean into the forgotten "blue dog" democrat and he'd get thunderous applause.
All of that is to say that I think the *ahem* "establishment" saw that Trump had half the country in the palm of his hand and cut a deal so he could lead them through the back door of the uniparty slaughterhouse with no questions asked because after all, no one questions the motives of /ourguy/, especially when he said things like "because you'd be in jail", "only Rosie O'Donnell" and "the wall just got 10 feet higher".
Neocons have adapted by wearing populism as an orange skinsuit.