Earlier this month non-profit organisations and companies including Google, Mozilla, Yahoo, and Reddit united to organise a day of action called Reset the Net. The event marked the first anniversary of Edward Snowden's revelations about the National Security Administration's extensive and illegal dragnet surveillance apparatus.

"Today, we can begin the work of effectively shutting down the collection of our online communications, even if the US Congress fails to do the same," Snowden wrote in a statement endorsing the campaign. The NSA is not going to stop snooping, but adopting encryption can make the mass collection of personal data more difficult and expensive. Why not put a little sand in the gears of their massive spying machine?

Reset the Net supporters were absolutely right to highlight both the torpid dysfunction of our political system and the value of encryption tools to individual users. Yet there remains something decidedly ironic about massive multinational corporations, whose profits depend on sucking up our personal information, spearheading a privacy campaign – especially given that some of their spokespeople have been wilfully tone-deaf on the issue in the past. "If you have something that you don't want anyone to know, maybe you shouldn't be doing it in the first place," Google executive chairman Eric Schmidt famously declared.

In addition to being a filmmaker and a writer, I'm an activist. While there's ample proof that the government monitors the political causes I am involved with, I find myself increasingly concerned about the social consequences of corporate surveillance. Private sector data collection presents a significant obstacle to democracy that we have yet to reckon with.

For all their righteous posturing, tech corporations did not join the Reset the Net campaign out of magnanimity but because Snowden's whistleblowing negatively impacts their interests.

Analysts have predicted that the American cloud computing industry's losses could reach $180bn over the next few years. Facebook and Cisco have complained directly to Barack Obama that the NSA's activities have hurt sales. Google, Twitter, and Facebook have had their reputations tarnished. For the big corporate players, Reset the Net was as much about image management as shoring up their infrastructure against NSA intrusion.

Companies such as Google and Facebook would prefer to denounce state surveillance practices rather than acknowledge the myriad ways they facilitate such encroachments. No wonder, then, that the Reset the Net campaign was silent on the issue of bulk data collection by for-profit companies for the purposes of targeted advertising and "personalised" services. "Companies have huge lobbying and political power that can be harnessed to help consumers," internet law expert Chris Hoofnagle told me. "But companies will not play along if the reform undermines or even raises issues surrounding their business model." We are lucky Snowden's revelations have caused large tech firms palpable economic harm, or they would have no incentive to grumble about government misdeeds.

But what happens when the interests of technology giants and civil society clash? A recent academic study gained some attention for revealing that ordinary citizens have virtually no independent political influence unless they affiliate with economic elites and corporate lobbyists. No matter how important, citizen groups that push back against the business interests of digital titans by advocating for things like robust antitrust enforcement, will have a difficult time gaining traction.

Privacy is a prime example of this dynamic. The companies that eagerly endorsed Reset the Net, and have formed the Reform Government Surveillance group, will not be joining similar crusades for stronger regulation of advertising-driven data collection. Yet the fact remains that if we care about online privacy we must check government power and dramatically curb the ability of firms to collect, store, and monetise our personal information. Civil society will have to mobilise directly against private interests despite the long odds.

Where technology firms could once be seen as the natural allies of the people against the old media dinosaurs and the state, that illusion no longer holds, particularly with regard to privacy. Advertising is the lifeblood of the digital economy, which means marketers drive the development of the "free" goods and services we depend on, concentrating wealth – between them, Google and Facebook control two-thirds of the mobile ad market – and distorting our culture. Even as they rail against the NSA, Google and Facebook continue to invest in ventures and announce changes to services that further trespass upon our intimate lives.

Some may dismiss concerns about advertising, but that view is shortsighted. As a filmmaker I balk at the soft censorship that advertising encourages (the implicit avoidance of content that may alienate funders and the corresponding promotion of click-bait) and I'm alarmed by the emergence of exploitative markets based on personal data. A recent White House review found that the gathering of personal information by data brokers opens new avenues for credit, housing, health, and employment discrimination.

This approach may be legal but it damages democratic values. In 1998, Sergey Brin and Larry Page warned that "advertising-funded search engines" are "inherently biased" and called for a transparent alternative "in the academic realm". Biased toward advertisers means biased against truth-tellers and advocates of social change, whose pockets are often less deep than those who wish to maintain the status quo and are able to pay to determine what we see in our news feeds. Today, despite its cutting-edge research on life extension, artificial intelligence and space travel, Google is utterly reliant on advertising dollars. Google apparently thinks that human immortality is easier to achieve than building a non-profit or publicly financed civic-minded search engine – in other words, a search engine that does not depend on surveillance for revenue.

However laudable and well-meaning, last week's Reset the Net protests, they skirted a fundamental problem. The business model of our leading technology companies is privacy invasion. Encryption is vital, but to truly reset the net, we will also have to challenge the economic logic that drives the current system, and devise funding structures that respect our right to not be watched.