This is fair and an important caveat. Pure arbitrage disappears quickly in the market. At the same time, though, no pure arbitrage profits is only necessary and not sufficient for full efficiency. An efficient market means no (or very few) positive expected utility opportunities still left around. The EMH still implies the price of shorts should have fallen until it became economically feasible to correct the mispricing.
This is fair and an important caveat. Pure arbitrage disappears quickly in the market. At the same time, though, no pure arbitrage profits is only necessary and not sufficient for full efficiency. An efficient market means no (or very few) positive expected utility opportunities still left around. The EMH still implies the price of shorts should have fallen until it became economically feasible to correct the mispricing.