While I would love to think this was due to evangelization or separated brethren coming to see the Truth of the Catholic faith, it is more likely due to illegal Mexican immigration.
Many (most?) of our bishops are far too milquetoast for any effective evangelization or any other task requiring real leadership.
Good point — time for the laity to force orthodoxy on them. The Pope is slowly weeding out lax bishops, but it will take time for top-down, unless we also have a bottom-up approach at the same time.