I firmly believe that massive, systemic, criminal fraud was a substantial cause of the meltdown. This Forbes article confirms my admitted bias that federal prosecutors/officials simply looked the other way and decided not to prosecute. There has been a narrative floated that there were no convictions because nothing "criminal" happened, but I believe this latter narrative to be total bullshit.
Are you actually surprised that the rules for the wealthiest and most connected are different than for the rest of us? Of course everyone on the inside is protected and always wins. They make all the rules.