VA was in Republican trifecta as late as 2014. At that point it should be clear their state is trending away from them. Why didn't they introduce Maine rule?
Same for NV, which have a Republican trifecta till 2016. Although they are not trending blue as CO and VA, it's much harder for R to win their state than D.
And now it's time for GA and AZ. The trend in GA is clear. Even if DeSantis or someone else may win it in 2024, it will become another VA unless some major realignment happens.
AZ is a little better, in the sense that phoenix suburb are not as bad as Atlanta for them. Yet they do not have a large rural reservoir like GA and NC. It may stay a swing state longer than GA, but becoming the next CO is inevitable.
So why don't then act now?
Hillary was below 50% in 2016 in virginia