Gerrymandering. One word that describes why Michigan no longer has a government that is representative of the electorate.
The 2001 reapportionment had given the GOP the votes it needed to gerrymander Michigan. They have repeatedly lost the popular vote for the Legislature only to win anyway thanks to favorable districts.
The advantage was doubled in 2011 after another GOP wave election. The results:
Democrats actually got plenty of votes, but Republicans made sure that most of them had no impact.
In the 14 congressional races, Democrats received more votes than Republicans:
Democrats: 1,515,716 (49.15%)
Republicans: 1,463,854 (47.47%)
The average margin of victory for winning Dems was 86,410; the average GOP win margin was 42,243.
(All of these numbers are from the current Secretary of State report and will likely change a little with the official canvass.)
In the races for the state House, Democrats received more votes but Republicans INCREASED their majority status:
Democrats: 1,536,812 (50.98%)
Republicans: 1,474,983 (48.93%)
The Republican maps turned a 61,829 margin FOR DEMOCRATS into a 63-47 "majority" for Republicans.
The average Republican victory: 6,389 votes. The average Democratic victory: 10,092.
In the races for the state Senate, the discrepancy is even more egregious:
Republicans received slightly more votes than Democrats, but turned a slim total-vote victory into a super-majority:
Democrats: 1,483,927 (49.23%)
Republicans: 1,527,343 (50.67%)
The Republican maps transforms that slim 43,416 statewide vote margin (1.4%) into a 27-11 advantage (71%) in the state Senate (one GOP victory, a 61-vote win, could be overturned on recount).
The average Republican victory: 15,107 votes. The average Democratic victory: 33,133 votes.
You don't need much voter suppression when you've figured out a system where your opponents' votes don't really matter anyway.
On that option of a citizen petition drive to end partisan redistricting:
Michigan's constitution has a strange restriction on citizen initiatives. Laws that include an appropriation, no matter how small, are exempt from being repealed through a petition drive. In the last legislative session, the threat of a successful petition drive to raise the minimum wage prompted legislators to pass their own (far less generous) minimum wage law and include in it a small appropriation, making the citizen petition drive moot. The same was done with TWO petition drives to overturn a state wolf-hunting season.
The only citizen alternative is to amend the state Constitution. Just getting a proposal on the ballot requires more than 320,000 valid signatures which would then be scrutinized and challenged by high-priced GOP attorneys. (Not long ago they successfully challenged a petition because part of it arguably used a 11-point font instead of 12-point.)
Barring a constitutional change in redistricting, the GOP has built a political perpetual motion machine that will automatically renew itself every 10 years through mapmaking that is more about winning elections than in protecting voting rights.