I think United still looking for the director of football first rather giving a Mckenna permanent job as head coach of the senior team, we have been finding one for years but haven't found one yet, even though Monchi were offered to join us but subbed us for Roma.
On other hands, Barcelona was impressed with Guardiola because of his work with youth sides, not because he wins a lot of games but the style of play has impressed Barcelona board most, that's one of the reasons they promoted him to senior coach and it is a huge step. If Mckenna changed a style of play in our attacking display and do most of our training session while Jose observing and win more games whilst playing amazing football, if it led to Mckenna's work, he could be one we would be looking to hire as head of coaches if Jose left. Mckenna know youth academy so well, he wants to give them getting more first-team experience, in a similar way as Pep Guardiola did the same thing and prompted many players from Barcelona youth academy because he has worked with them before.
Mckenna played one of the most amazing football in the U18. Mckenna fit United's identity so well as he easily could be tied down to long-term, more like 15 years or so, he's still young and United fans, what can we ask more? I think our board and Mourinho see something else in him, they want to promote him to senior from youth academy because of his work with academy and style of play, hopefully, he could become our Pep/Zidane version coach in the future.