Yes, Mata has just come off a fecking operation that put him out for a large portion of the season, with very little match fitness, let's throw him into a vital second leg of a semi-final when he only played a few days ago.
You use the words 'all of them' when in reality, it was, what, one game now that Lingard has been preferred to Mata? Today?
Carrick is fecking 36 and played against Arsenal a few days ago, Fellaini given his suspension is fit and raring to go and scored the vital goal. It hasn't been all season and you yourself even know that's bollocks, in fact a huge portion of our league campaign (apart from the beginning) was with a middle 3 of Herrera, Carrick and Pogba.
Only time I remember Darmian being preferred over those players is for either rotation or for certain tactical match-ups (like against Chelsea etc.) otherwise, Young was getting played heaps before his injury.