I'd say you're the most correct of the bunch in this discussion. In the vast majority of business ventures the vast majority of your population is not going to be a customer, ever.

Look at statistics of things like apple vs android users and their purchase behaviors. Targeting the Apple users will likely bring in far more money in the end.

Also it's not your job as a company to ensure the user stays up to date and secure. Old devices are really just a risk these days.