I don't believe Shaw would see that way. The thing is Evra went here as a grown player, a fully formed one. And a good one, but not a star, thus a 5-6 mil price. Whatever anyone thinks of Shaw is irrelevant, he is perceived as a superstar in the market. He is only 19, he just played his first full season as a prem starter. And he understands he needs to play not 50% of the games, not even 70 but close to 90. And if MU in not ready to believe in him and give him a starting role, he well may stay with Saints for one more year. Think about it, he is young, surely he has not overgrown the team, he could well develop with them, especially if Pochettino is staying. Next summer all top english club will still want him. Maybe even City will want him, cause their LB options are not quite great and secured.
So i think to convince him to join now will be very, very hard.