Many of the county wide offices were close in 2018 and 2020 and the GOP won a few but the fact that it voted to the left of the state this year and a county of its demographics and demeanor voted for someone like Pritzker in 2018 over someone like Rauner shows it is a very uphill climb for the GOP.
And it may be one of the very few counties Pritzker carries in 2022.
I mean, Pritzker only won it with a 2 point plurality and McCann got 3%. I think it'll probably go Republican for governor. People there do NOT like taxes/Madigan.
Could trump have won it if Bernie was the nominee?
Don't think so, but it would have been within single digits. Trump is a really horrible fit for the area. Though Kasich or Rubio would have very likely won it against Sanders.
Is it winnable in 2024 with the right GOP candidate?
Unlikely except in a GOP landslide but who would have predicted Starr County, TX flipping in 2020 back in 2016?
Possible the GOP wins it in the gubernatorial race but also possible its one of the very few counties Pritzker wins.
I see the point you are trying to make but must pedantically point out that Starr County, TX did not flip this year; Biden still won there by 5. Also, Starr County had an R trend in 2016 too, so its R swing this year was an acceleration of an existing trend, rather than a reversal as a DuPage County R flip would be.