Do people have too much brand loyalty?

There have been several incidents when companies change something about their product, the public gets upset/angry about the change, and then go right back to buying the product in the end. The companies, which can for the most part ignore the public disapproval, are almost unaffected because people are still buying the product. One time when this happened was when many companies downsized the product while increasing the price in the recession.

So, what do you think about brand loyalty in today’s world? Also, can someone name more examples of when the above scenario has happened?