You're 100% correct for the scene in SoCal. But this particular discussion is shedding some light on the scene in AZ, where there are now 4 teams at the DA/ECNL level in a geography where the player population could probably only field 1.5 or 2 elite level teams in any given age group. Theoretically, there will be more parity below the top couple of teams. My initial question was about the balance of talent between DA and ECNL in those 4 clubs.
With regards to DPL, I don't think it's much worth any discussion for the simple fact that, as you've said, the DPL teams are always the 2nd team at the club. No matter what league a club competes in, when your team is the 2nd team (b-team) there is almost no stability from season to season. This is true of the EGSL or "ECNL II" teams that we used to see all over the place, and true for all the 2nd teams playing Flight 2 or Silver Elite here in SoCal. What you get is a few players that are good enough to play at the next level and for some reason or other haven't been selected for the top team at that club (politics, inept coaching, "too small" for the A team coach). Rarely, some of them stick with the club and keep grinding until they get pulled up, but most of those players leave for the top team at another club. The rest of the team stays only as long as their parents continue to buy the idea that they will eventually get promoted, which is usually only one or two seasons. This is not a DPL problem, it's a "b-team" problem, and you see it at all clubs, at all levels. Managing your player's growth is a balance between ambition and satisfaction, and the DPL teams are doomed to always have too much of the first with too little of the second.