I don't agree i'm overthinking it, i'm simply trying to get a clear picture of what is actually meant by the ground symbol in a circuit schematic!
You mentioned the "return path", this is the first time anyone has called it that in this thread and that makes things a bit clearer.
I think part of my confusion is that there are two things under the umbrella term of "ground", and they seem (to me) totally unrelated.
Firstly you have the safety issues and the connection (for whatever reason) with the real ground, chassis or whatever.....
Secondly you have this return path, whose purpose is sometimes to close the circuit (although not in my circuit example in this thread) and give you a short cut route for any component in the circuit to a common point of lowest potential, typically just before the negative terminal, or if you're using a rail splitter, to that point in between the two resistors.
So in this usage, the word "ground" could be substituted with "return path".
And if we were only talking about circuits in intergalactic space, the term "ground" would be a meaningless and confusing obfuscation.
Once these circuits are returned in a spaceship to planet earth, we could happily continue using the "return path" nomenclature, adding, when necessary, "this point needs to be connected to the chassis or real ground or whatever".
So could someone look at the circuit in the first post and choose one of those connections to ground (apart from the rail splitter connection) and explain why, at that point, the designer said to himself "right, here we need to connect to the return path"? (he probably thought of it as "ground"

)