See for yourself, take a look at the shelf space of a major supermarket in your area. Note that Pringles has very little shelf space and certainly not on a end feature, aka known as an "end cap" in the industry.
Brands PAY to get their product in a prominent position, and note that brand entries in the last few years such as Stacy's, Pop Chips, Food Should Taste Good, and Tostito's have major shelf exposure while Pringles has very little exposure. In many markets you would have to look for a long time to even find the product.
Paying to get into prime shelf space will cost Kellog's big time on this one. And with the current trend to use thicker dips such as hummus, guaccamoli, taziki, and salso a Pringles chip is too frangile to work well.
IMHO, I would venture to say that 2 weeks after the Super Bowl, which is a HUGE week for snack products, that the decision to unload Pringles was made to rid a declining brand to Kellog's.
Travel outside the US and you'll be amazed and impressed at how often Pringles turn up - everywhere! They're practically a global currency, nearly as common as Coca-Cola in convenience stores, newsstands and kiosks around the world.
Seriously, over the next week visit supermarkets, super centers, and big box retailers and note the shelf space of Chips. Take a few minutes to note where the products are end capped and just how much unit volume is done from end caps. Realize that Kellog's will have to pay a premium to locate Pringles to the end caps, and if the brand does not sell in high unit volume the markets will move it back.
There is a REASON why supermarkets put brands on end caps, is because THEY SELL. Pringles does not perform well, that is why you will not find it in a prominent position in a market.