The odds of heads rolling, going by previous non-attempts at holding these agencies responsible for their actions, seem to be low enough that they're quite happy to engage this behaviour without fear.
And as for bringing about a change that would see future incidents causing them to be held accountable? I think the average person, and therefore the population, feels entirely powerless in that regard. I mean the US voted for a supposedly liberal, progressive President who even has it on his campaign website [1] that he would "Protect Whistleblowers", who has then gone on to prosecute more whistleblowers than all other President's combined [2].
So it's no wonder why people feel powerless, and it's no wonder why any change to these situations is certainly not coming in the visible future.
