I believe QT was sold to Ameritrade in 2006, about three years before TD acquired TOS. TD probably wanted two things from the QT purchase:
1) Decent charting capability, 2) the QT paid subscriber list for its new TD customer potential - (and perhaps a third reason - preventing a competing brokerage firm from buying a superb package and using it as a marketing tool)
Let's say that Jerry (and Mazel) had 10,000 paid subscribers and twice that in non-paying, ad reading users. If I recall I was paying around $40/50 a year. So that would have produced about $400,000 to $500,000 a year in gross sales. So Jerry probably got about $3M to $5M for his company. Who knows. Anyway it has been 5 years since the sale. TD began restricting the brokerage interface almost immediately and tried to get QT users to switch to them for brokerage services. Three years later TD bought TOS. TOS has two charting packages, their own and the Prophet system which TOS had purchased. Why support three?
Assume that there are now 5000 paying QT users @ $60/yr. $300,000 is not much for supporting a package and there are probably no remaining users that plan on switching to TD/TOS. It was just a good business decision even though it didn't make loyal subscribers very happy.
Jack