It's not an assumption, it's a fact. And I'm not speaking as a mere gamer; I'm speaking as an indie developer, programmer, and translator. And precisely, a project of this nature is rarely financially viable, much less in an alpha state.
In this situation, the author is telling you right now, "Try my new game. It's not the full version. I know it has bugs, but it's a 'project.' I'm still polishing it, but I'd appreciate your support if you think it has a future."
And that's the key word. "Project." I'm not invalidating the fact that you point out the narrative, plot, and mechanical inconsistencies in the game, but don't try to make it look like you were given half-cooked chicken at a family home you were invited to for dinner.
Your words, and it's not my place to say them and I'm sure the author won't even read our conversation (if you can call it that), sound more like complaints than constructive criticism or comments for the good of the project.
It's clear you're just someone who enjoys playing and has no knowledge of the process of making a game. What you consider a minor change like changing sprites is a process that takes hours and days. It's not changing one image for another, it's changing an entire system based on the needs and vision of the project.
Creating, modeling, rendering, ensuring that systems don't crash just because the image is 10px smaller than the previous one or the animation isn't compatible with the new version of Ren'py. Even something like 0s is enough to undo weeks of progress and start repairing everything from the ground up and backups. And I'm only talking about "superficial changes like sprites and dialogue tweaks."
If you think it's so easy to create a game, why don't you make one? There are plenty of ideas on the internet. There are communities like roleplaying that can provide you with coherent plots and stories if you need them. The Ren'py creation tool has a demo, and if you need it, I can provide you with resources to help you learn how to use it.