Frankly, this is cope. GAL has (relative) strength in the west and specifically California, but outside of (and inside of) the west, ECNL is currently and clearly the more prominent/ dominant league. It's not even a question. That won't always be so, but it's wild to make a statement like "If Surf goes all in with the GAL League, then ECNL is toast..."
Unless US Soccer (or to a way lesser degree NWSL) steps up and and declares "we won't id/roster players unless they play in 'X' youth league," then there is no incentive for anything to change.
And we know from history that US Soccer had an opportunity to do just that with DA, and they didn't freeze out other leagues.
We all love GAL. I get it. But let's be realistic.