Also not an expert :) I thought plasticity is an O(hours-days) learning mechanism. But I did some research and there is also Short Term Plasticity O(second) [1] which is a crucial part of working memory. We'd need that. But it seems it’s more of a volatile memory system, eg calcium ion depletion/saturation at the synapse, rather than a permanent wiring/potentiation change (please someone correct me if this isn’t right :) ).
So I guess I’d just clarify “read only” to be a little more specific - I think you could run multiple experiments where you vary the line of what’s modeled in volatile memory at runtime, and what’s immutable. I buy that you need to model STP for thought, but also suspect at this timescale you can keep everything slower immutable and keep the second-scale processes like thought working.
My original point still stands - your subjective experience in this scenario would be thought without long-term memory.
1: https://www.frontiersin.org/journals/computational-neuroscie...