It's a small part, but it's a part. I think Snowden has done his fair share of trying to inform laymen and stir up giving-a-fuck. If he wants to switch to working on tech, he could accomplish nothing and still come out far ahead of the rest of us. ;-)
The existence of a decent open-source router can't do much against a U.S. National Security Letter.
While we certain should care enough to force our government to stop being our adversary, there will always nevertheless be adversaries. You have to work on the tech, too. Even if you totally fixed the US government, Americans would still have to worry about other governments (and non-government parties, such as common criminals, nosey snoops, etc), where you have no vote at all. You will never, ever have a total social/civic solution which relies on, say, 4th Amendment enforcement to keep your privacy. I'm not saying your chances are slim; I'm saying they're literally 0%.
Furthermore, getting our tech more acceptable to layment acually would correct some of the problems inherent with NSLs, improving the situation even in a we-still-don't-give-a-fuck society. If you do things right, then the person they send the NSL to, is the surveillance target. The reason NSLs (coercion with silence) works is that people unnecessarily put too much trust into the wrong places.
For example, Bob sends plaintext love letters to Alice, so anyone who delivers or stores the love letters, can be coerced into giving up the contents. OTOH if they did email right, then if someone wanted to read the email Bob sent to Alice, they'd have to visit Bob or Alice. That squashes the most egregious part of NSLs, where the victim doesn't even get to know they're under attack.
That's true whether we're talking about email, or even if Bob and Alice get secure routers and VPN to each other. One of them gets the NSL ordering them to install malware on their router.