I get the frustration, I really do. I too am a reader and at foremost a player. I too have my experience of getting disappointed in canceled projects - and not just for free projects too. I've had my share of pledging for PAID projects and in the end, they got canceled.
You do have the right to be frustrated.
But I'm sorry to say that you don't have the right to tell someone not to do a project unless they can finish them, especially if they're doing it for free.
I have my own life and interests, and they will change. Can you predict how long you can stay interested in one fandom/series? You can't. And I think personally I was in the P5 fandom for quite long compared to others. Including project planning and setting things up, I worked on this game for a full one year in the background before the very first devlog in my free time. If you add the time after that that I spent, it adds up to almost two years. A lot of things change in two years.
I am but a simple human being trying to find a creative outlet and wanting to share my passions about something, as fleeting as it may look for some people. And I'm not even asking for any remunerations whatsoever for the free time I willingly put into it. I am not a content machine. You can call me unprofessional if you'd like - I am not a professional developer afterall. If you don't like my style as a creator and can't 'trust' me then feel free to find others.