By all means educate us then.
> There is $.10 of surplus here. Who (if anyone) should get it, how, and why?
That seems like kind of a philosophical question. Who ever should get any surplus? A better question might be, how can non-HFT traders arrange to capture the surplus currently claimed by HFT?
> if there is no HFT involved how would you propose that this situation be resolved?
The situation now is that whoever is fastest gets the surplus, even though being milliseconds faster provides very little utility. If you remove all HFTers somehow by magic but the situation remains that whoever is fastest gets the surplus then whichever of the buyer and seller can adjust their prices faster would get it. But suppose we go a different way and have the exchanges sort it out: Automatically send all offers to buy or sell to every exchange where that security is traded and allow the other exchanges several seconds to match bids with asks. The highest bid is always matched with the lowest ask on any exchange and the price paid is the midpoint between them. That seems inherently more efficient than creating a huge financial incentive for private actors to shave invisibly small slices from the amount of time it takes to trade between exchanges.