He has been getting alot of playing time, but only sparingly has he been used in his preferred role. If you could remember Sturidge at Chelsea, the situation was similiar towards getting few games in his preferred role.
Which is why if he does go, a lot of similiarities will be drawn to that of Sturridge departure at Chelsea. With the former(welbeck) having a comparable ceiling to the latter, it is safe to assume that if he goes to a club like Arsenal, he could be a catalyst towards a title winning team in the future. If Martinez remains at Everton, they could also win it with the way they have been playing. Manchester United would obviously survive without him because sir Alex Ferguson has laid the foundation for the club to not enter despire, but his departure would hold question mark for future acedemy products and what would have been with Welbeck leading the line or having a role in our team.
Question mark towards players like Lingard, who despite his excellent pre-season might aswell start looking for a new club. The Keane brothers, Pearson and Wilson aswell, if we continue this policy of overlooking our acedemy players for established players. Young managers like Martinez, Pochettino, and Brendon Rodgers has shown that it is not all about looking for established players to build a great team and other managers should really aspire to that standards.