Such commissions exist in 8 states-And the resident waterboy bitch misrepresents data. I see California, Hawaii, Washington and New Jersey as marked in green. “Several”.
Also, even “non-partisan” committees sometimes result in the mapping of districts to help solidify the power of incumbents, as is the case in Washington.
And in California, due to their jungle primary system, Democrats have run ads to support fringe Republican candidates to dilude the playing field, which is simply a variation of gerrymandering. See also the 38th district in Los Angeles. Independent commissions do not always balance cities, counties and neighborhoods with racial, incumbency or political considerations.
Republicans have taken it to the next level to solidify their power in some states, but as I said previously, the Democrats do not have clean hands.
Ohio voters instituted rules to prevent extreme gerrymandering. Pennsylvania is protected by their state Constitution with current districts drawn by the state SCOTUS. The GOP has opposed both measures.
Your example of Washington's maps & California advertising are both red herrings & a form of gish galloping.