In the Chicago area, it seems the “conversion” has already taken place. Almost all “slow” events (2 days, with main controls of at least 90 minutes) are already run using increment. For faster events (1 day, with controls like G/65 or faster), delay remains king.
The one major exception seems to be CCA, which uses delay (albeit 10 seconds instead of 5) for almost all of its events.
Bill Smythe