> plus all the carbon emissions of actually using the ICE part of a hybrid.

If we are supply constrained on batteries, you can't just ignore this. It's e.g. either 1 full electric and 5 gas cars, or 6 plug in hybrids.

You don't have to ignore the lubrication oil etc. as you are saying. Just look at total carbon for the two alternatives (not the only options, less cars and more buses is another option).

You are presuming a zero sum game here, that no matter what "6 cars get made" and that we can't just slow production until supply catches up.

Slowing production may be bad for the laborers of the company in the short term as it probably means fewer factory shifts and fewer workers get paid, but it also means less downstream supply of cars on the market, potentially an increased pressure on price to meet demand, so also potentially good for the company bottom line if they demand higher prices during the constrained period.

Slowing production would be great for total carbon output.

Keep using old gas car (for average about 3 years) by making 1/6 of BEV is better than selling PHEV (I expect zero emission for 90% workload, and lower carbon emission than BEV in production) now for decarbonization? I think decarbonization isn't just avoid ICE.

Slowing production is my bus option. Also without something like "cash for clunkers," slowing production potentially keeps less efficient stuff in play for much longer.