While that's sincerely heartening to hear, I'm curious about the numbers of desertion vs. mortality. I really don't know how they match up.
Perhaps all the Republicans who are open-minded and capable of changing their minds, such as you and Tim, have already done so? I don't know what more it could take to convince a Republican to abandon the party now that hasn't already happened. Sure, if there's an economic downturn, people will almost certainly leave in some number, but not because they decided that there's something fundamentally wrong with the party.
More than "desertion," the issue can be analyzed as long standing incompatibility.
The GOP, for basically my entire life (which is long) has contained what Hillary called the basket of deplorables. Nixon appealed to them directly in the southern strategy response to the civil rights movement. As more of the unconcerned middle took offense to open racism in government the appeals had to be toned down to dog whistling by Reagan, but the deplorables were still loyal enough. GWBush had to fight for the margins because even dog whistles to the deplorables were considered offensive to a huge majority by the turn of the century. The deplorables stayed loyal because they had nowhere else to go, but the shunning took a toll.
Romney ran under a party mandate that recognized the deplorables as a dead end street. Open racism is just too widely offensive now and without diversifying the GOP was headed to eventual death. Romney didn't do a great job of it, but he did try to shift the brand further away from the deplorables. Trump's calculation was that this path to long term survival is irrelevant in the short term and he seized the party by direct supplication of the deplorables. It worked to get him elected, because it brought disgruntled deplorables back to the polls and the rest of the GOP in the immediate sense had nowhere else to go. But that 'rest of the GOP' is, in fact, just as incompatible with the open appeal to the deplorables as anyone else.
That incompatability is clearly illuminated by the term RINO, which the Trumpists apply to at least half of all Republican voters. If you don't openly state that Black Lives Matter is the
real racism and should be put down with extreme prejudice by law enforcement using anti-terrorism laws, you're a RINO. If you don't support "the threat of Sharia law" as justification to enact Abrahamic law, you're a RINO, and of course there's no place for anything but a man cleaving to a woman under that law in their opinion. They are done being hidden in the attic like so many drunken uncles caught fondling their nieces and nephews, the deplorables now consider themselves irrevocably as the new face of the GOP. Oddly, against even the most basic rules of mathematics, they think they can shrink the party by half and still be a majority.
If they 'succeed' in driving half of Republican voters into the ranks of the Democrats no amount of gerrymandering or voter suppression is going to carry the day, even in the deepest sorry states of redness. What might carry the day is if the Democratic party makes a very strong point of making their newly available voters unwelcome. They had nowhere to go
in the immediate sense, but they are looking now. The midterm showed that.