It’s a bit of a strange argument that developers can feed their families _only_ if they sell their software on a subscription basis. Nobody wants to developers to starve. At the same time it is not a _duty_ of users of a software to make sure the developer’s family is fed. It is a business. Developer sells something, and the buyer gets value in return. Subscription is just one way of making the buyer pay more(may be hoping that they forget that they were paying for it amidst 50 other subscriptions).
It is perfectly fine to say “I expect to feed my family with this work. So I want to charge $bigamount”. Then your buyers chose whether your software is worth that or not.
You may also say, “I prefer a recurring income, and don’t want to charge one time. It is my prerogative.”, but arguing that one cannot feed their families any other way is disingenuous.
