Although lawsuits are one way to fight gerrymandering, they are expensive and can take years to resolve. A lawsuit can be risky: the court might rule against you or make changes you don’t agree with. Challenges may have to be filed after each redistricting.
Putting the redistricting power into the hands of an independent, impartial citizens commission is a better and more permanent solution. Legislators would find it politically ruinous to try to bring the process back behind closed doors and shut the public out.