Think of it this way. Let us take the number two reason for such breaches of personal privacy(money being the number one reason), i.e. terrorism.
If you were actually a foreign terrorist, and for some insane reason you did decide to discuss your "super secret plans" in email or over phone, unless you are completely retarded as well, you will use your local dialect instead of English. And you will use common words or phrase *in your own dialect* as previously agreed codewords. You will NOT communicate in English. So NSA might flag the foreign language conversation as suspicious, but I doubt there will be a perfect automatic speech translation in place that can immediately translate. And even if you had someone translate ever single piece of foreign language conversation, you still will have to deal with guessing what the code words mean.
In other words, a sweeping eavesdropping program will get you zilch unless you even for a second believe the other guys to be total morons. They might be insane, but they are not at least that. Only time you will have results by eavesdropping is if you already knew someone to be a terrorist, and were monitoring all their calls and tried to assume everything to be a terrorist communication.
The other situation where you will have results is, if we change the definition of results to "eavesdrop on our own troublemaker citizens and political opponents and have blackmail material on them to ensure we stay in power". Now *those* are the guys who will communicate in a language your eavesdropper program can listen to and collect material on. Think of collecting bits and pieces of info on every time someone mentions your political opponent's name and sifting through that to see if you can find anything on him to ensure his complete submission.
And unless you want to have a de facto dictatorship cemented even further and no chances of having even a semblance of democracy, feel free to sacrifice privacy. You will eventually sacrificing your freedom or liberty too.