Those are indeed very valid and reasonable points (Especially the one that suggests that Ds only carry Texas in 2008 (D+7) types of landslides (Since the state is around R+10 relative to the nation).
But I disagree with the assumption that the speed of D trends in the Suburban counties (At least the sunbelt ones) are subject to whether or not theres a backlash againts an incumbent party but rather whether or not the candidate that it's a the top of the ticket can temporarily slow them down or due to another very unique circumstance.
Margin relative to the Nation
2000 | 2004 | 2008 | 2012 | 2016 | 2020
Collins -49 -41 -33 -35 -19 -9
+8 +8 -2 +16 +10
2000 | 2004 | 2008 | 2012 | 2016 | 2020
Williamson -41 -29 -20 -25 -12 -3
+12 +9 -5 +13 +9
As you can see the trend is pretty similar accross every election however when theres a candidate with what seems a unique appeal (Romney 2012) the trends temporarily halt, but at the next election trend twice as hard (Maybe that's why New England saw a big swing towards Biden? A reversal to the mean?).
Of course I could be very wrong on this and I could be seeing the wrong pattern here but this seems what the date indicates.
Well 2012 is the only time that a Dem reelection bid this century and the number one point I am making is that trends usually slow down in a presidents reelection bid. 2004 and 2020 had Republicans in the White House and 2000, 2008, 2016 were open elections which are the most prone to huge variations.
As for 2000-2004 overall trend in Texas how much of it is the Nader factor being gone in 2004 cause I think Bush won by a larger marin in 2000 but got a higher % of the vote in Texas in 2004. Texas overall really didnt trend much democratic at all from 2000-2012 if you add in the Nader factor into this.
2000: Bush beat Gore+Nader in Texas by 19.17 points and lost by 0.5 points in the popular vote meaning Texas voted around 19.67 points more Republican the nation
2012: Romney beat Obama in Texas by 15.78 points and lost by 3.9 points nationally meaning Texas voted around 19.68 points more Republican than the nation.
True, given where Nader performed the best he probably took a lot of the vote from Gore but if you give Gore his share of the Vote the national margin gets bigger as well so the trend stays around the same:
Collin (If you give Gore Nader's share of the vote)
D 26 (-47)
R 73
National (If you give Gore Nader share of the vote)
D 51 +3
R 48
Trend: (Without Nader) -50
Trend: With Nader -49
And yeah, the trends in a non-incumbent year are slightly bigger at the state level but sunbelt suburban counties ones don't really differ that much (At least as far as I can see)
(Average state trend)
2020: 2%
2016: 5%
2012: 3%
2008: 5%
2004: 4%
2000: 5%