If CARB is looking to trim CVRP costs, they should start by remembering what the purpose is of this program -- to incentivize sales of clean vehicles in California.
Many of the vehicles eligible for a CVRP rebate are compliance EVs. Some of those manufacturers have already decided they won't sell any more than the bare minimum number of EVs for compliance -- the CVRP rebate has ZERO effect on the total number of these compliance EVs that will be sold.
OTOH, Tesla is not only serious about selling EVs, it's they only vehicles they sell. Incentives for Tesla vehicle buyers does stimulate more EV sales, this is readily apparent from Tesla sales in states and countries with the highest EV incentives.