Why do calculator manufactures like to reinvent the wheel?

[Harold A Climer]

This has been an interesting thread, but I would like to come at this from a Physics teachers perspective.
I have taught students in the Physics Dept. at U.T. Chattanooga since the middle eighties. My first calculator was a HP-25C in the 70s,then a HP-41 in 1983.
I also have a 48SX,48GX, and 50G.
I think, IMHO, that cell phones with calculators are one one most ill-conceived ideas (for students that is) along with the Trickle Down Economy.
I have had students use cell phones,etc. to text test questions to students in other sections during exams. I have also found students send data from experiments to other students so the other students did not have to come to lab to turn a report.
It is no wonder certain calculators and devices are prohibited for use in Engineering and Surveying exams in the U.S.
In many Engineering classes here at U.T.C. certain calculators are not to be used
for faculty generated exams.
In the Physics Dept. Cell Phones,personal laptops,tablets,etc.are not permitted for labs and exams. Each lab station has a Dell desktop and other equipment sufficient to do any of our lab experiments.
After a student graduates cellphone,tablet are probably permissible.
However considering the cheating scandal with the U.S. Air Force involving the Nuclear Missile officers, I wonder even about that.
Stand alone calculators are sill needed.