The national numbers support your main point, that MLS Next is a step ahead of ECNL Boys (and everybody else). But the gap in team performance between the two is going to vary by area. You're right, that in AZ, it sure looks like a decent MLS team would be expected to flatten even the best ECNL team. There are several goals difference from Barca to the top ECNL team for example, usually Arsenal in most age groups. This isn't the same in other geographies. Yes, in most cases the MLS N teams are certainly on top, but the gap to a top ECNL team is quite narrow, sometimes less than a goal per game, let alone the 3-4 goals seen in AZ.