Yes and no. With a chain you're certain some % is going back to HQ. That's not the case with a co-op. So even if the goods are sourced outside your area - and chances are some are going to have to be in this era - the co-op still wins in terms of money "retention".
If the co-op banks with a local credit union, that's another plus. Chains likely aren't doing that either.
Again, check out the book. He had great insights and great ideas.
That may not be the case anymore if the coop sources everything from the same sources Whole Foods does.