The big brother problem is becoming irrelevant, not because of changes in encryption, but because we’re voluntarily giving up our privacy.
For one, as mentioned upthread, in general the government isn’t reading emails in any meaningful way, they’re gathering metadata about online communication. In general, the metadata almost as useful, and in many cases even more useful than the actual text of a communication, at least from a monitoring standpoint. That is, the overwhelming amount of communication is relatively benign, and it would take resources many orders of magnitude beyond what is currently available to monitor and parse that data while still getting a decent level of accuracy.
OTOH, building social networks provides relationship information and that can help them determine who are potential threats more easily. It’s not unlike a large game of Linking to Bacon, where one person’s connection to another can be determined by how closely they link to other threats.
Personally, I still have issues with the collection of metadata by the government, as while I don’t have any particular expectation of privacy that I have a relationship of some sort with a person I may have sent an email to, but I don’t considering sending email, in general, to be consent to the government knowing the nature of all of my relationships.
That said, I have reasonably consented to that sort of stuff from other companies, but that’s in exchange for particular services. I have a Facebook account, and obviously Facebook knows all the people I’m friends with and to what degree I communicate with them. If I used Twitter, I’d reasonably expect that they’d know who I sent tweets to and who I follow. Or even for something older, I have a credit card and make most of my purchases with it, so they know when and where I shop. The key difference between these forms of monitoring and what the government may do is that I’ve made a reasonably informed consent to this monitoring, it’s a necessary part of the service, and I can use alternatives or just plain stop using it whenever I like. That is, if I don’t like Facebook monitoring my relationships, I can not friend someone on there or just stop using it. If I don’t like my credit card company knowing about my purchases, I can use another card or use cash. However, the only way to not have my online communication monitored by the government is to not use it, which is still possible, but significantly more limiting.
Unfortunately, though, this is the general trend of technology. When new technology becomes available, often it means trading some degree of privacy for other conveniences. I don’t think this is inherently a bad thing, as long as that trade off is reasonably understood and traded with informed consent, but I think it’s virtually inevitable that in order to be a functioning member of a modern society, there will come a time when one is essentially coerced into giving up privacy. That is, for now, it’s still possible to not use facebook, email, twitter, smart phones, etc. But how much longer will it be before it is all but impossible to conduct business, make purchases, find a job, or whatever without using modern technology?