There's no way to know or demonstrate that information
, or anything else, is instantaneously
transferred from a to b. In fact, instantaneous
propagation is a contradiction in terms. If a and b are changing instantaneously, then they're changing simultaneously. And there's nothing in our observations of our world, our universe, that suggests that simultaneous, spacelike separated, changes in a and b imply a causal relationship, or any sort of communication, between a and b. Rather, what this does imply is that a and b are part of a larger system, or that a and b have something in common due to a common cause.
Wrt some formulations (eg., inferred wrt standard QM and explicit wrt dBB interpretation) a and b can be said to change, or are explicitly encoded as changing, simultaneously. So, if one wants to give this some sort of pseudo mechanical
meaning, then one might say that information is being instantaneously transferred between a and b. But this isn't really mechanics. It's just an assumption that can't be verified or falsified. Ie., a physically meaningless statement.
That's news to me. I would say that observations indicate that our universe behaves contrary to the notion of block time. That is, it's evolving and transitory. But that certain theoretical constructs/eventualities suggest block time. And, afaik, the theoretical stuff that suggests block time (or that contradicts observation) is more or less routinely disregarded/discarded.
Because it's unwarranted wrt extant observation and mainstream interpretation of theory.
Your title asks why superdeterminsim isn't universally accepted. My guess is that it's because superdeterminism doesn't refer to anything other than determinism. Determinism might not be universally accepted, but I think it's the predominant assumption and starting point wrt virtually all of the physical sciences.
Why not? Are you saying that the assumption of determinism implies action at a distance? Or superluminal propagations?
Ok. So far this is just determinism.
You've arbitrarily assumed a starting point (ie., initial conditions) that isn't influenced by past events. But we can just as well assume that wrt whatever you want to assume as a starting point there are antecedent events, ie., some prior history/conditions.
So, as far as I can tell, superdeterminism is a superfluous term, which actually just refers to determinism.