Many investors in mortgage backed securities lost quite a lot in 07-09. Your statement is false. The fed bailed out the big banks but smaller players wrote down many positions to 0.
Sure, not every dollar of every mortgage backed security was rescued in that way. But the imbalance you reference was yet another way that the rescue really didn't set up the economy for a healthier future - especially larger sophisticated investors were rescued, and both smaller players as well as many people bore the hardest hits.