The massive losses in legislatures that have occurred since 1994 have been mostly due to a combination of realignment and reapportionment driven by the GOP gains. That part is done now. The realignment that has been ocurring in those D to R areas is largely done, and reapportionment probably could not get any more extreme than it is now.
Reapportionment or redistricting? Reapportionment is not partisan driven, it's simply done by population. And when I look at party control of state governments, after the 2000 census it was still fairly balanced, even if the southern states were being run by blue dog DINOsaurs.
State government control:
1994:
2000:
After 2010, that's when you really see the shenanigans ramp up.
