I think anyone buying at market A is foolish because market B evidently will always have the better price.

Market B sellers would also be foolish to continue selling on B when they can get a better price selling on A. But I guess for this hypothetical the sellers on B are forced somehow via this flaw to continue to sell even when they don't want to, or have better options.

flawed in such a way that it won't adjust to increased buy volume.

What devilry is this!? : )
what is the market without the individuals voluntarily setting their own price. This flaw is pretty wild. I suspect it has to be either the exchange will go insolvent because the displayed books are not representative of the individuals placing their own orders, or there is some mind control device effecting the behavior of these individuals. It could also be a result of a non-free market where access to the different exchanges is restricted or limited, in which case the arbiters are a blessing for those poor soles unable to trade where everyone else can. : )