Regulations calling for technical progress need to be matched to the rate the progress can realistically happen.
Mandate something that's not currently possible, and manufacturers may just chose to pay the fine, or discontinued something useful that could have been kept if they had more time to improve it.
If the mandate is possible but the technology isn't to the point it's reliable, you get a lot of angry customers. A good example is the low VOC paint that peeled off cars in a year or two, which also raises the question of whether having to paint the car twice pollutes more than painting once with the old formula.
With EVs, the claim that the batteries last 10 to 12 years suggest they aren't appropriate for the average driver when the average car on the road is 12 years old. We've had a discussion and that 10 to 12 years figure may be pessimistic. But it's the number that's out there. If it is real, somebody who has an older car is going to spend less patching together a 15 year old gas car than replacing it with a 10 year old EV. If EVs can't deliver the longevity people need, the result could be more old cars with bodged together repairs when we could have had newer, more efficient gas cars.
And even if EVs are more durable than that, the perception that an EV is a ticking time bomb once it reaches 8 years or so is enough to persuade many people to vote for politicians who don't push EVs too hard.
