I’ve been saying since the primaries that the best plausible scenario was for Trump to get the nomination, then botch the election and drag the weirdos and loyalists in his party down with him.
Trump has spent years purging anyone that was moderate, even slightly principled, or just willing to put the good of the country ahead of his gigantic ego. Not to mention the way they treat the party’s warchest as their personal piggy bank, and it’s rank and file staff and volunteers as disposable. He’s made a party that’s blindly loyal to him, and which is a huge threat to the country, but which is ultimately far less effective as a party.
A more normal candidate would likely be dominating the race given public opinion on the current administration and the economy, to say nothing of the obscene amount of money being thrown around. But instead, Trump looks like he will cause the Republicans to underperform for the fourth time in a row.
If Trump loses dramatically enough and drags his people down with him, the party will likely collapse in on itself as opposing factions get locked in a power struggle. Plenty of big donors just want lower taxes and to not have to deal with regulations, and they will probably want to shift the party away from the MAGA weirdness and back towards something normal that isn’t going to alienate voters on all sides of the aisle. I wouldn’t be surprised if a few of the more prominent anti-trump Republicans suddenly got a big boost in support, and a lot of Trump’s parasites suddenly find themselves getting driven out.