It is not irrational on the part of the developer -- I've definitely felt this too. The problem comes from the fact that practically everyone has subscription fatigue these days, and each of us probably has only a few pieces of software we truly care about enough to want to support them out of the goodness of our hearts.
But everyone wants us to pay $10/mo. It just isn't sustainable from a consumer perspective.
But everyone wants us to pay $10/mo. It just isn't sustainable from a consumer perspective.