Telles isn't great and that's when the realisation kicks in.
Two average left backs = average left back play
Shaw is not average, he's bloody solid even on his average days, obviously not one of his howler days, but every slip and criticism grow over the top for some players like him Maguire, Pogba, Fred...
Alex telles on the contrary is just a classic example of an average player, he's got that one skill - his crossing which he overuses and unfortunately was brought only as a squad player, instead of us aiming to upgrade Shawwe brought in an average palyer who will take time to get rid of now. Player who struggle to defend in almost every game, offers no speed, no dribbling and often hollywood crossing with very little success rate. Nothing against the player, just a fair evaluation.
Shaw on the other hand after absolute amazing last season suffers like HM from the Euros and being overplayed and growing criticism of the overal MU, Unfortunately he's not one of the leaders to say I will come back stronger and make this team to play better on his own but his form will show if the form of team is low. Still a great youngish player with good ability and least of our worries now.