Shareholder scrutiny preceded and caused the depositor scrutiny.

Edit: I guess the point is that without the threat of depositor scrutiny, shareholders would have no reason to care about SVB's poor investment decisions, since they were only a problem in a bank run scenario caused by depositors. Failing that, the only risk to shareholders would be regulators, and regulators weren't doing anything about this problem, they were enabling it. I think you're right about that.