I have noticed a phonomenon where progressives typically win in urban, heavily Democratic, and inelastic districts.
An example of this manifesting itself could be Alex Morse losing a primary in one of the most elastic districts while Jamaal Bowman won his in an inelastic district.
Why is this? Is it because geographically small districts are inelastic? (They are.) Is it because swing voters don't like progressives or value incumbency more? Something else?