NXN is too limited in scope. You want to know how deep FootLocker was compared to NXN? FootLocker had 20 guys come through the mile together, whereas NXN was already decided 1600m in both the boys and girls races.
I take it you didn't watch NXN, then.
FLN was a continuous string of 3-5 wide at the mile (4:53).
NXN was a continuous string of 3-5 wide at the mile (4:40ish), though there were three guys just ahead of the pack: Michael Hall, who finished 15th, leading the way and Cerake (#4) just ahead of Tony Russell (#11). Everyone else was in that massive pack that was just as tight as FLN's race, despite the fact it went out 10-15 seconds faster.
If you wish to educate yourself, here are the videos to the races.
(mile @ ~6:15)
(mile @ ~6:00)
Also note that, at the ~2k mark, the announcers mentioned how the whole group (~40 runners) were within about 5 seconds from the leader. 39 runners were within 5 seconds of the leader (look at the splits), and 46 runners were within 6 seconds of the leader at NXN - hard to say FLN was really a tighter bunch.
NXN didn't string out until about 2.5k, when a group of five (Wilmot, Anderson, Russell, Geberkidane, and Haney) finally started to break away from the pack. Race time, it was about 7:40-7:45 when Wilmot went to the front. By 2.9k (8:55 race time), it was the lead pack of 5.
At FLN, it started to string out at about 2.6k when Hardy went to the front (race time ~8:10-8:20). By 2.9k (9:00 race time), it was a lead pack of 7 with one guy hanging on at the back.
In other words, the race broke open at about the same time at both events. FLN had a couple more guys hang on when the initial move was made, but by the end of the race more of those runners dropped off (at the end of the race, 11 guys were within 16 seconds of the winner at both NXN and FLN - with a smaller gap behind them at NXN as #6 was 10 seconds off the winner compared to FLN where 1 guy finished within 11 seconds).