I would say it lies in the nature of being an artist that the products are unique and unpredictable. Competition applies to a much smaller extent. You write one great novel at age 20, should you be able to live on the royalties for the rest of your life? In the end the consumer decides anyway, if they buy enough books at a high enough price, then you can.
As I wrote in another comment, there is also a moral aspect to this. If people willingly pay your subscription fee, then this is what it is. But do you find it good to sell your software at an inflated price in order to make yourself a nice life? How would you feel if everyone else did the same, if the supermarket staff would all only work half a day, make $45k a month and put the bill for that onto your grocery prices? I bet you would hope that competition solves the issue, otherwise your subscription income will no longer afford you a nice life.
Why is this different from software?
The software priced here is very cheap. DevUtils costs lifetime less than what an hourly wage of SWE intern costs.
I don’t even know what logic is implied in here regarding the supermarket staff.
do you think the same for authors and musicians?