While I wouldn't say they won't still get in trouble, the problem for banks in the sub-prime crisis pre-2008 was they were lending tons of money people who shouldn't otherwise be borrowing money. They would underwrite no-doc loans and loans to people that were not properly vetted. Those sub-prime loans were then packaged into investment vehicles that were leveraged, often several times, and unwitting buyers didn't know that the mortgage backed loans were actually junk, so when home prices started going down, those mortgage backed securities lost a shirt ton of value and everyone in line got hammered. Had the banks not been bailed out, our country would look far, far different today.
Where we're at today, the banks aren't anywhere near as leveraged as they were back then, but that doesn't mean they won't have other issues. They'll suffer some in a downturn, but I don't expect them to be bailed out again. Who knows though. Could happen, I'd just say it's not likely.