Marylin, if I may be so bold,
First and foremost, let me state for the record that I am not a teacher of English, never have been and never will be. I am not replying through experience, simply personal impressions.
I agree with your statement when it applies to the World market - Mr. Russell will never rule the world with this piece of software. Certainly, there will be people who will not be able to relate to it, and others who simply can't access it due to the limitations of their available technology.
I do, however, believe that there is a wide enough market for people to be interested in a product like this and for Mr. Russell to do well from it.
It would entirely depend on which market segment the software was being aimed/marketed at. There are plenty of people who have decent computer & internet access, and who need or desire education in the English language. There are millions and millions of people from every walk of life who want assistance with learning English. Access to the needed technology is increasing massively on a daily basis.
I honestly do think that a product such as this could do well, and I wish Mr. Russell good luck in being able to pull this off.