$P=BPP$ without good PRGs?
To put this in complexity terms, could it be possible that P = BPP and EXP has polynomial-size circuits (so no general derandomization)? Relative to a generic oracle you do get P=BPP for all input lengths, and EXP in P/poly for infinitely many lengths, a partial answer to your query. I don't know an oracle where P = BPP and EXP is in P/poly, but I'd think it should be possible.