I love Massie losing but step back and look at the difference between a Dem stronghold like NYC and a Republican stronghold like KY 4:
Dems endorse their extremists (see AOC/Mamdani) who talk extreme but moderate in office. Dems are able to effectively organize online through systems like the DSA to normalize these radical thoughts with many moderate young dems radicalizing (Calla Walsh being a prime example). The Democrat party itself is low on resources and while it initially resisted this, they seem to have given up. Status quo (Eric Adams/Cuomo) is dead.
Republicans seem to prefer the status quo with a no name winning solely off Trump endorsements vs an incumbent who went for the Podcast Right (Tucker/Owens/MTG) vote. What's interesting is that Massie clearly knew this wouldn't work in his district, hence his local ads pretending to be on Trump's side. This election was laying the foundations of his future media career. Regardless, it shows that the Podcast Right has a strong minority in Republican strongholds. Unfortunately, we cannot actually measure the power of the Podcast right due to Massie's faking of Trump endorsements very likely corrupting low information Republicans. The Podcast right is the strongest right wing movement online but at best, they cannot win a primary with everything stacked in their favor.
Dems are heading towards extremism, Republicans prefer Trump and the status quo.