Being able to buy GM for Dimes on the Dollar, some Billionaire would snap it up, like Buffet or Slim
That's how Capitalism is support to work, not 'too big to Fail'
GM failed.
But its Bones were were good, there was profit to made with that.
Yeah, just like how they saved our nation's flag carrier, Pan Am!
To be a bit more serious, GM's fundamentals were not good. Buffett was around during the recession and passed on GM just like every other investor because although GM could be had cheaply, its downside risk was catastrophic. They didn't ask for their loans to be secured and do managed bankruptcy as a first option-- it was their last option. When they did that, everyone with financial investment in GM, including the leadership of GM, got wiped. Trying to find some private ownership group would have been financially beneficial, but they didn't do that because no one would have taken on GM at that time. You'd have been insane. You're not just buying GM, you're buying their future liabilities as well.
GM is massive, and had significant liabilities with pension and healthcare costs that made a private takeover basically impossible.
GM's bankruptcy was $54 billion. This isn't a billionaire buying their hometown newspaper to keep it afloat, GM's assets were significantly diminished against their massive debt and future liabilities. If they couldn't get their loans secured, they were not going to have the liquidity to keep the lights on. Ford didn't face this problem because Alan Mulally right before the recession hit, took out loans leveraged against every company asset as a hedge in case a recession hit, because much like GM, Ford was operating with an alarming lack of reserve cash that wouldn't have been sufficient to keep the production process going if auto sales tanked. They simply did not have revenue to keep the factories running if their monthly revenue declined. Ford didn't take those risky loans for fun, they did it because their operating situation and cash reservers were that dire, that they risked the company's independence to shore the situation up. (EDIT: Forgot to mention that the reserve cash was important because they were at junk grade so non-secured loans were both not offered by banks because the company had no feasible repayment plan, and the interest you'd have needed on the bank side to make the loan risk worth it would have made such repayment impossible. Beyond that, not only would the loan be risky, on the bank side, you're not exactly swimming in cash either in fall 2008, so you're absolutely not loaning GM that money and waiting to see if they can pay you back for a 9% profit over 5 years.)
Ford supported the bailout of their competitor, because GM totally going under would have been an H-bomb on the parts suppliers, which is also a secondary issue with the "someone will buy GM and bring it back" idea. Once the factory that makes a very specific type of o2 sensor goes under because GM was 55% of their orders, it's not like that infrastructure will sit their waiting for your GM v2.0 to pop back up. If GM went under, Ford likely would have gone under next, because they share a number of part suppliers that would have ceased operation without GM orders.
I've owned a Chevy Cruze that I liked, I think GM makes a number of good products (and some horrible products!) but they were going to go under if they couldn't get a loan to provide them operating revenue after auto sales tanked.