Another of those questions might be 'what if Jude Bellingham had signed for Ole Gunnar Solskjaer's side last summer? The harsh reality is he might not be playing for England in a major international tournament had he done so.
Former Birmingham midfielder Bellingham rejected United in favour of joining Dortmund a year ago, having met Ed Woodward and Matt Judge at Carrington in March with his parents. Instead favouring a move to Germany where he felt he'd be given more trust and opportunity to develop.
It certainly looks like a risk which has paid off.
During his debut season in the Bundesliga the 17-year-old midfielder played 46 times for Dortmund, netting four goals and notching four assists in a staggering 2,821 minutes of senior football.