Why do calculator manufactures like to reinvent the wheel?

[Han]

Even if schools no longer required calculators, they would still hold a niche market. It doesn't matter how fast these mobile devices get, how fancy their screens are, and how cheap they can drop. The fact that there are some folks who absolutely hate many keys (e.g. note the demise of various Blackberry devices) and there are those who absolutely have to have dedicated keys for efficiency means there will always be calculators around. I for one hate phones that have buttons -- it generally means the phone is thicker than is necessary.