The put and call short, long option graphs don't seem to reflect the fact that a short call or a long put position holder could purchase the assets before maturity especially if that price is below the strike price, and gain more through the difference between that price and the price at maturity.
So is it always the case that the assets are automatically bought and sold at the maturity date(or maturity hour or maturity second)? But can it ever be perfectly simultaneous? What if there are price fluctuations between the time an asset is getting ready to be delivered and the actual moment of delivery?