1964 Chevrolet Impala - Question on rain sensors

For my 1964 convertible, I had designed and installed a system so the top would close automatically when the car was idle and it started to rain. Why is this feature not installed in all convertibles?

Because of the problems the manufactures and dealers would have if it failed to work when it was supposed to .

It was introduced by Cadillac in the 1950’s and is currently available in some high end convertibles