It’s less A processing problem and more a collection asset and storage problem.
320 million people in the US. If every person only makes 1 hour of phone calls per day I get that many of the people in the US aren’t old enough to be calling on the phone but people spend way more than an hour a day on their phone talking so this is a conservative estimate anyway. That’s 320 million hours of recording per day. That’s 116.8 billion hours a year. It takes about 1.3 GB of space for an hour of audio. That’s 151.8 billion GB of audio per year. We haven’t even started on the text messaging and internet usage for just the phones. Add in all the internet traffic etc.
Also how do you propose NSA actually collects the traffic in the first place. Cell phones by definition do not have a long range, hence the cells. Are you going to place, manage and maintain collection assets in order to get all this collection. There are over 400k cell sites in the US.
Oh and when someone calls you from a different cell that conversation would be collected twice and recorded twice.
Oh and when you talk on a cell phone its actually using 2 frequencies so the hours would actually be doubled.
So yeah. Your living in a fantasy world.