You've got your finger on the pulse of something that open source has always represented to me: freedom of the creator and others to just... do what they want with it (subject to the license of course).
Don't like what the main developer is doing with it? You're free to fork and continue on your way if they don't see it your way. If you lack the skills or time to do that, that's your problem - you're not entitled to the maintainers' labor.
The freedom cuts both ways, and by adding in elements of social contracts and other overlays onto the otherwise relatively pure freedom represented by OSS, you end up with the worst of both worlds.
THAT ALL SAID - there's an important distinction between a given piece of software that's open source versus a "true project", which is larger-scale, more contributors involved, might be part of mission-critical systems, etc, where the social dynamics DO need to careful thought and management.
But even that seems to be more a question of specific types of OSS business models which is related but not the same as the licenses and overall social dynamics around OSS projects.
Before it becomes anything else code is first and foremost art & personal expression.
Code is a very fun form of literature at heart.
Other attributes may be tacked on later, it may be integrated into and transform into an engine or company that has rules and regulations.
If the author treats it as only art, with license choices, etc. then they aren't entitled to treat it like anything at all, it's literally their personal expression.
And this is recognized in the physical world as well. More than people realize, some buildings that are incredibly dangerous are considered sculpture effectively. There is a rickety castle built by mostly one guy in CO that meets this criteria.
I think you are trying to make the point that there is the ethical argument to consider the impact of a decision if your project has grown large enough that there is major dependence on it.
I do agree there is an ethical obligation to make some effort to consider impacts like that, and make an attempt to inform users of your intent, but that's all it is. No one is obligated to be ethical, either, when it comes to a personal project with volunteered time and effort.
I think the argument of obligation becomes a stronger if your project has taken on a lot of contributions from other parties. And yet, those contributors must acknowledge that they are willingly doing so with no promises except the posted license terms.
Don't like what the main developer is doing with it? You're free to fork and continue on your way if they don't see it your way. If you lack the skills or time to do that, that's your problem - you're not entitled to the maintainers' labor.
The freedom cuts both ways, and by adding in elements of social contracts and other overlays onto the otherwise relatively pure freedom represented by OSS, you end up with the worst of both worlds.
THAT ALL SAID - there's an important distinction between a given piece of software that's open source versus a "true project", which is larger-scale, more contributors involved, might be part of mission-critical systems, etc, where the social dynamics DO need to careful thought and management.
But even that seems to be more a question of specific types of OSS business models which is related but not the same as the licenses and overall social dynamics around OSS projects.