They lost their last thought leaders, who are now called Never-Trumpers. But even these people held on too long, when the evidence emerged that a whole bunch of their beliefs were founded on sand. I think most sensible Republicans exited under Dubya Bush, once it became clear he wasn't listening to moderates.
There's no persuading the people left in the GOP because there's no underlying reasoning to argue with. It's faith and prejudice all the way down.
Not sure when I became aware of identity politics. But I am definitely bored to death by endless, one-sided victim claims and accusations that anyone not toeing the party line is prejudiced. For myself, I long since concluded everyone is prejudiced to some extent about nearly everything, that prejudice is natural and useful in some circumstances (eg people are often prejudiced in favour of their family), but also damaging in others (eg if someone lynches a person because of their skin colour), and that we do well to limit the application of prejudice when inappropriate as far as possible in more marginal circumstances. But I don't wish to condemn people for many of the sorts of things that many folks jump up and down about. Most folks try. Everyone fails one way or another. It's only the people with nasty patterns of behaviour that concern me. Unfortunately, the GOP contains a bunch of them!