You are stating this like it would be some certainty...I didn't start this 'what if' game. Others started it by saying he wouldn't have followed MvdP in PR.
That's a very unsubstantiated 'what if' in Roubaix, much more than the other way around.
We have been robbed off a great race / duel, and it's easy to see how the race would have evolved with Wva in it. The first MvdP attack in Arenberg would haven been covered by WvA, but with Van Dijcke also there and Philipsen / Pedersen flatting, WvA would have riding hard with MvdP to keep the gap, and there is a big chance they would already have been away with a group no more than 5.
Even if it came together, WvA would have covered MvdP's attack in Orchies, and either WvA would commit and it would been a duel, or WvA would ride defensively like last year, riders would be able to come back /bridge across and we would still have had a race. How far that race would have gone before e.g. MvdP breaking free (or not), we don't know.
But those that say WvA wouldn't have been able to follow just becasue the meagre competition yesterday didn't even try, have not watched previous Roubaix editions.
Its just as (or more) likely that Wout would have been caught napping and caught up with Mads, they would work together for a while as the gap extended.
Someone said it before, we have to stop comparing Wout with MVDP or speaking like they are of the same level.