Re: "responsible for products sold since they were aware of the problem"
"What should they have done, taken iPhones off the market during that time?"
This argument would have more weight if they hadn't launched and marketed several brand-new models in the time between learning of the vulnerability and implementing a fix for it. These would not have required pulling from the shelves, could have been pushed back a month or two so they were shipped post-patch, and were being sold with a significant flaw which the vendor was aware of but the customer was not.
That does provide feasible grounds for legal action:
a) Apple knew that both the 8 and the X had a severe security flaw
b) Apple had a timetable for when they were going to fix said flaw, or at least knew when it was going public
c) Apple were aware that the fix for the flaw would impact on performance (even if only a little) and yet
d) Apple chose to push ahead with the launch prior to the fix in order to benefit from the Christmas sales period.
A decent lawyer could spin that to win some damages, since the sales proposition Apple was offering was inaccurate (either in the level of security claimed to exist in the product, or else in the level of performance of the product, since either one or the other is inaccurate depending on if you deploy the patch or not), Apple knew it was at the time, and Apple took actions which allowed the company to benefit from the information disparity between themselves and the user.
Fair or not, there's enough there for a good lawyer to argue with and at least get a hearing.
What I don't see is how any lawyer, no matter how brilliant, could point to an Apple TV purchased in 2010 and claim that somehow the purchaser deserves compensation for a security bug that was discovered outside the useful life of the device. The ridiculous timeframe they're trying to cover makes it obvious this is just ambulance chasers, and amateurish ones at that. I wouldn't be surprised to see this case being thrown out based on the absurdity of the scope.