If this is true, why when I go into any Electronic store for a darn case for my Google Android phone, all I find are shelves and shelves of Iphone 5 cases of all sorts, and but a few HTC and Samgsun Galaxy cases.
Because while market share can be an interesting metric, profit share is another one. People who buy the higher-end devices are actually willing to spend money on them, both on accessories and apps. That's why Apple and Samsung combine for 108% of the profit share in smart phones (yes, that's over 100%, the remaining companies operate at a combined -8%).
It's also because if you look at total units sold of specific models, you'll see iPhone at spots #1 and either #2 or #3 (current model and previous model), with a form factor that only changes every two years - a lot of units and a stable design make it easy and safe to manufacture things like cases that depend on the form factor. It's a lot more hassle, and blows up any economy of scale, to make cases for dozens, if not hundreds, of model variants.
Go to Ebay or Amazon. Plenty of cases for a fraction of the cost.
Other than the top Samsung phone at any given time, nobody has enough market share to warrant shelf space for the numerous android phone model cases.