Coombs I don't think I agree with this. That has always been Klopp style even back in Dortmund days. He has a great track record of bringing and nurturing players. He walks to talk and is willing to put trust in his youths instead of endless spendings.
We have also seen managers like Pep, Poch (see his Chelsea team yesterday he rather blood young players than give game time to useless fringe), Ange etc all giving plenty of debuts and game time even in difficult matches.
Arteta has never changed in this aspect. From the Willian days to now, unless his hands are forced he don't like to put trust into any academy players but rather prefer experienced fringe players if push come to shove. Plenty of evidence for that even in dead rubber Europa group games