I would say they are incapable of positive change. (Others will likely point out they eventually die, which is perhaps the ultimate change. I mean while living.) But they are capable of negative change ..... consider going from nominating Willard "Mitt" Romney to nominating the felon in 2016. Of course, they did so in 2020 and 2024, indicating the inability to change you noted.
We do see hints, at the very least, that some of them are worried about their chances in the mid-terms is they continue to kiss the felon's ass. More, some are aware that the felon will soon have lame duck status, with the reduction in his power decreasing at a pace as fast as his physical decline. His focus on building a temple dedicated to his memory might suggest that he is aware, as Jim Morrison sang, "The future's uncertain, the end is always near. (I refuse to confirm that I have set aside a special gram of hashish for that day.)
There will be disagreements between different factions that increase. For example, some are expressing rage at Tucker Carlson. Imagine when he enters the 2028 presidential primaries. Think of when the primaries are ongoing, he announces that Marjorie Taylor Greene will be on the ticket with him.
They will destroy themselves. The biggest question, in my opinion, to paraphrase Jack Nicholson, is when god created republicans, was it a mistake? A leak from the universal lab? If so, there might be a cure. A vaccine that involves pouring bleach up their asses? But if it was on purpose, it's a curse and they have no hope.