Understand that a lack of privacy isn't a problem until it's a problem, e.g. someone has something against you and needs something to wield against you. The government & large corps. will happily use propaganda against you, and it's easier for them to find dirt on you with little to no privacy.
Think of it this way, the average person has something in their past they're probably not happy about that could be misused against them in a political way, if say, they ever wanted to be involved in politics. Enemies will use this, and enemies now have all of the data they want.
Honest question: do you really think they store every piece of communication that flows through the internet, just waiting for some random teenager they spied on to run for president? The way I imagine it the data runs through a lot of filters that look for evil words/phrases/whatever. Those few emails/sms/etc will be stored and sent to NSA analysts. I doubt they care about the usual type of "dirt" you use against people.
I am against the illegal spying, but what you're saying seems like a conspiracy theory.
Think of it this way, the average person has something in their past they're probably not happy about that could be misused against them in a political way, if say, they ever wanted to be involved in politics. Enemies will use this, and enemies now have all of the data they want.