The article dismissed bailin in a short sentence at the end when I think it is one of the most significant difference between 2007 and now.
Bail-in is the right given to the regulator to declare a bank non viable and to impose an instantaneous, extrajudicial, chapter-11. Basically writing down bond holders over the course of a week end, and possibly any unsecured, non deposit-guaranteed creditor of a bank, and in this way auto-recapitalising the bank. It has been used a few times in Europe already, though not on major institutions yet.
I am not aware that in the US only holdco debt is bail-inable, so I am not sure why the article infers that the tightening in borrowing cost between holdco and opco means investors don't believe in a bailin. I'd say that they rather don't believe in a bailin of the holdco only.
In the UK the regulator stated its approach of bailin-ing the holding company first before considering the operating company (bank), and you see a clear spread between the two, particularly initially as banks are starting to issue debt out of the holding company (and therefore a lot of bailin risk is concentrated on a small amount of debt).
Another important difference is that unlike 2007, a default risk of banks is priced in. The market has the capacity to absorb losses, in fact it is designed for that. The issue comes when losses occurs in places where they were not expected (money market funds, "AAA" MBS, bonds issued by major financial institutions, these were what cause the 2008 run on the banks). Then it gets really messy. But even now (in rather benign credit markets), bank credit spreads are still significant.
What worries me is not banks themselves, but sovereign debt and central bank capacity to react. We forget that as recently as 2011, investors were getting seriously worried of a country like Italy defaulting. Italy has now even more indebtedness, and a populist government that wouldn't think twice about making a radical action on its foreign debt. And other countries like France aren't that far behind, with a massive reliance on short term borrowing and no political willingness to control public deficits. Central banks on the other hands are still all-in on QE (at the current rhythm the Fed will have fully retired QE well after the next cycle kicks in), and with very low rates. So what levers are they going to use next?
And yeah if states collapse, the financial system under them will be wiped out.