Did not know about that element, but it does not change the perspective.Don't forget CARB has made out of state business owners use DPF equipped trucks to run on CA roads.
Even with California requiring out-of-state commercial vehicles to install DPF hardware, this is still a static requirement that does not (easily) allow for other technological improvements. Put another way, even though this is an arguably cleaner alternative than what the non-California States allow, it still locks-down the emissions on a vehicle and requires it to remain the same over the vehicle's life.
As a part of the perspective that CARB stands in the way of progress is that there are other States which either leverage or mirror the CARB standards. So, by CARB making an expensive and onerous task out of showing that a change is beneficial, it has a wide net of effect for all the other States that follow-along with this philosophy.