What is the main difference in the business model for GM, before and after the Government takeover?

There is no difference. Goverment Motors should have had the doors locked. If they can't build vehicles that people will buy in huge numbers, then they should close. It was simply a bailout of the UAW. I only drive a Toyota because I know if I buy a GM, Ford, or Chrysler that I'm really making a donation to the Democrat Party because the UAW only donates to Democrats. No thanks.