I don't believe the car analogy is good. And neither is the Note one.
In both of those cases the products can cause serious harm without any third party implication. The brakes would just go of or the battery would explode during normal function.
However, in the Intel case there has to be an attacker that actively exploits an issue in design.
To me this would be like making a class action suit against all lock vendors because they can be bypassed with the right set of tools. The fact that this affects everyone (Intel more than others) and that it took 10 years to find grants them some excuse. Also the architecture is not secret as far as I know so anybody could have audited this. They most probably did do so and found nothing until now.
Now, I do not like Intel communication around this and if it comes out that they knew this for years and decided to sit on it then it would be a different story.
Class action lawsuits are useful when there is negligence, or bad intent but in this case what could it possibly solve?