Again, this isn't about what can be technically possible. As the other poster wrote, it is a criticism towards the decisions of the GTK developers. That someone else could take the code and change it, is completely, absolutely, 100% irrelevant. It has nothing to do with the comments here, they aren't about if it is technically possible to add a compatibility layer on GTK3 or GTK4 or whatever nor who will make it.
It is ALL about the GTK development team's decisions, including the decisions that make a backwards compatibility harder.
Also caring about backwards compatibility isn't something that can be bolted on top by a 3rd party, it is something the library has to keep in mind in the design phase. And it isn't something that can be thought as a separate component, it is something that has to be at the same level as everything else. Expecting that it is something that "shouldn't hold up a GTK release" is a completely wrong way of thinking about backwards compatibility - a project that cares about being backwards compatible considers it as important as any other change (new features, bug fixes, etc) and not something to be an afterthought.
> The GTK developers are just ordinary people like you or I who volunteered to work on it, if you want to change this situation then you or someone else can step up and become a GTK developer and work on this. Then you can say they care about it :)
Sure, they may be (i do not know) and they have all the rights to ignore backwards compatibility - it isn't like i'm paying them to work on their library or be in a position to make any demands out of them. But that doesn't mean i wont say they do not care about backwards compatibility.
> I think it is incorrect to say they don't care about backwards compatibility anyway,
It is absolutely correct because this is what they have repeatedly shown.
> you seem to agree that they would meet that minimum required to claim backwards compatibility.
No, i do agree with that, what i agreed with is the definition that keeping code running is the absolute minimum one would do to provide backwards compatibility, but i never claimed that the GTK developers care about it. These are two different things: one can not care about backwards compatibility, yet still provide that minimum amount for it for practical and strategic reasons to entice people move to the next version.