Remember years ago when UTD were good. We/I would mock some of their youth players for not being good enough. They played well because of the class around them and the system.
Then AF would sell them to West Brom or somewhere and they would look ordinary - Wes Brown, Cleverly, Welbeck for eg.
That was because they were system players which looked great when the system was working - they wasn't actual quality themselves however - that is Lewis.
When the system is working then he could slot in, but trying to actually hold down a position for himself when the system wobbles highlights where his actual skill set is - that of a Wycombe Wanderers level.