The "All Dodges and Chryslers" story is bogus, as you know.
It is possible, however, for alloy wheels to leak. I have this problem on one of my cars. It's very annoying, but I've learned to live with it.
However, if you didn't have this problem before you got new tires, it's unlikely that the wheels are leaking. And if your car has steel wheels, they are NOT leaking.
It's also true that tires lose pressure as the air temperature decreases, so tires mounted indoors, where the air temperature is 65-70 degrees, will lose pressure if the car is parked outside in winter. But I don't think that's your problem.
I think your problem is "major chain and not a local shop." Major chains depend on volume to make money. The get you in and they send you out, as quickly as possible. Convenient, aren't they? But they lose money if they have to do anything "extra" to your car, such as remount the tires, so they tell you lies to make you go away.
Local shops, on the other hand, thrive on customer service and repeat business. They want you to be happy, and they will usually do whatever it takes to make sure you are happy with your purchase.
Dodge and Chrysler vehicles do NOT need to have their wheels replaced at 80K miles. This is the biggest load of BS I've heard in some time. How do they think they can get away with something so outrageous? Go back and DEMAND they do the job correctly. You paid for new tires, they shouldn't be a problem.