It’d really surprise me if people stayed on West Beach without a sea wall. Those people leave when a hurricane is coming in.
In general I agree with your assessment about the west end. However the one factor that could change this equation a bit is that I think the ones on Bolivar Peninsular got caught with rising water blocking their way out much earlier than they though it would happen. So I don’t know if that could have happened to those on the West end of Galveston Island.
Did you hear the people who tied themselves together walked in chest deep water to High Island?