FWIW you are grossly misinformed about soccer in OK and TX.
Oklahoma has one DA team and two ECNL teams. One of the ECNL teams is one of those joke clubs that ECNL unfortunately added in the aftermath of the split (Oklahoma Celtic), and the other two teams are mediocre, but Energy (DA) is better than TSC (ECNL) in just about every age group.
In Texas, the two best clubs by far are FC Dallas and Solar (who both put their top teams in DA). Then there is a 2nd tier of good clubs in Sting (ECNL), D'Feeters (ECNL), and Lonestar (DA). Then a group of mediocre clubs in Dash (DA), Challenge (ECNL), Texans (DA), Classics Elite (ECNL), Solar (ECNL), and Albion (ECNL). Plus another joke in Sting Austin (ECNL).
The Texas ECNL conference is still pretty good, but the DA league is vastly superior, and it isn't close. And I understand that player movement this summer is widening that gap. And the future looks to only exacerbate the difference. DA starts at U13 in Texas and Oklahoma, and all six of the TX-OK DA clubs have top 50 teams (per YSR) coming in, while ECNL has only one such team (D'Feeters). Sting can't even field a competitive 07 team, so they are apparently playing up an 08 team for ECNL next year.
And elite players didn't leave DA clubs for ECNL. In fact, the opposite has happened. Of the 24 Texas players called into youth national team camps in 2018, 23 of them play in the DA in 2019, albeit almost all of them are Solar and FC Dallas girls (Sting and DFeeters have none anymore as their last handful moved to the DA clubs).