There are many WINDOWS operated computers that could use the SERIAL PORT to connect to external devices.
Most computer owners do NOT know how to connect a program in the computer to aa external device by means of the SERIAL PORT.
As a result there is reduced demand for external devices that could operate from te computer through the SERIAL PORT.
What is even worse is the neglect the SERIAL PORT has received from computer programmers:
the USER can not find a source of information as to how to output/input from a program to an external device connectd to the SERIAL PORT.