This week we are likely to see yet more drama and revelations in the saga that is the Leveson Inquiry as the prime minister's former spin doctor Andy Coulson and former Sun editor and horse owner Rebekah Brooks take the stand. You may be starting to tire of the blanket coverage but please don't switch off just yet. There are big issues at stake.

Last week, the Culture Select Committee's report on phone hacking condemned senior staff at News Corp and concluded that Rupert Murdoch was 'not fit' to run an international media conglomerate. Some commentators and politicians in this country immediately tried to paint this as a partisan squabble between Murdoch-haters in the Labour Party and his defenders in the Tories and claimed that the controversy has undermined the credibility of the report itself.

This misses the point entirely. Everywhere else, the story is focused on one fact: that a parliamentary committee, having scrutinised the behaviour of Britain's biggest media company and criticised its corporate culture in the most vehement terms, has concluded that the man who is ultimately accountable for the company's successes and failures should no longer be allowed to run News Corp.

Campaigners in the US, for example, have now demanded that the regulator, the Federal Communications Commission, revoke News Corp's Fox Television licences while the chair of the powerful Senate Commerce Committee, which oversees communications, has written to Leveson asking if he has come across any evidence implicating News Corp in illegal practices either taking place in the US or affecting US citizens elsewhere.

None of this will come as a surprise to those people who have long contested Murdoch's grip both on the UK media market as his well as his unhealthy influence on the political process. But there is a more important question that the constant focus on Murdoch threatens to hide: how did we get to a situation where one company was allowed to accrue so much power and influence? What does it say about our political system that it has bowed down so consistently to the compulsive allure of media moguls? What kind of democracy allows itself to be bossed around by figures who lack any kind of formal accountability?

Our obsession with the fate of Murdoch is understandable but it risks limiting the full implications of the phone hacking scandal. The fixation on one man means that we are likely to miss out on the broader, structural questions that ought to be at the centre of this debate. Instead of second-guessing the identity of the next CEO of News Corp or speculating about whether the company is going to withdraw from the British media market, surely it is necessary to ask some broader questions: what kind of ownership rules do we need to prevent these events from happening again? How big should media companies be allowed to grow in a democratic society? What does 'freedom of the press' mean in contemporary circumstances and is it really under attack by proponents of a tougher regulatory regime for British newspapers?

Media power cannot be understood simply in relation to single individuals. Instead it is the product of a system that systematically places the pursuit of profit and influence before the needs of its citizens. At the start of the phone hacking crisis, powerful voices in the press argued that this breakdown in ethical practice was confined to a few 'bad apples' in the News of the World.

Now that we have evidence of a cover-up at the highest levels in News Corp, of a 'culture of illegal payments' inside the Metropolitan Police, and of emails that point to collusion between media lobbyists and a government department, it would be a shame to amplify this mistake and to narrow down the problem simply to one company and one man.

Now, more than ever, power without responsibility - in the shape of proprietors who bully their staff, police who accept cash and favours from news organisations, and politicians who design policies with a view to securing a favourable reception by a powerful media - needs urgently to be checked. The vast majority of the mainstream news media failed to anticipate the economic crisis, failed to hold bankers to account, failed adequately to challenge the justifications for austerity and so have failed democracy. We need something radically different.

Rally for Media Reform, 6-8pm Thursday 17 May, Central Hall, Westminster. Speakers include Hugh Grant, Tom Watson MP, Owen Jones, Mary-Ellen Field, Jacqui Hames and many others. For more details, go to www.mediareform.org.uk.

Follow Des Freedman on Twitter: www.twitter.com/lazebnic