I wouldn’t even say that was the point of Flashpoint. The point seems to have been to tell an alternate universe story centered on the Flash.
It’s pretty clear from interviews that Flashpoint was planned before they decided to do a reboot – it was a big Flash story that became a big DCU event that would have led to the universe returning more-or-less to normal (no doubt with a few changes and some of the new Flashpoint characters retconned into history), but then DC decided to use it as the springboard for the reboot.
As near as I can tell, the only way that Flashpoint #5 transitions into the new 52 is that double-page spread. The final scene would have worked just fine in the old DCU if Kubert had drawn them in the old costumes.