Could this scandal bring down the government? That's not entirely fanciful. But even if not, their every step will be hobbled through to the next election, stifling any high-flown protestations of political virtue. Bang to rights, in Andy Coulson, David Cameron imported into the heart of his operation an agent still in the pay of a powerful political and commercial manipulator. The cascade of revelations of the intimacy between the Cameron entourage and the Murdoch empire saps the government's authority. That's the "shadow of sleaze".

Cover-ups unravelling is what sees heads rolling. The picture emerges of a party deciding long before coming to power to gift Rupert Murdoch a media and cultural dominance beyond anything seen yet. So much is known already: Cameron made a hasty speech threatening Ofcom with the chop. Jeremy Hunt rejected Ofcom's advice to refer the BSkyB bid to the Competition Commission. Cameron was completing what Margaret Thatcher began – and all for what? Fickle support from Murdoch's press.

Why does this make the foundations of No 10 tremble? After all, the story has never changed. The Guardian and a few others have written it time and again, ever since Thatcher first broke every rule, twisted every regulation and bent EU law to give Murdoch a newspaper and television dominance unthinkable in the US or most countries. We have ranted and railed helplessly over the decades, pointing our finger every time politicians of any party kowtowed to the man they feared. Blair as godfather to his child? Brown's last-minute currying favour with a real-terms cut to the BBC licence fee? Democracy was bound to be suborned. That's precisely what competition law is there to prevent: monopolies are monsters hard to chain once set loose, nowhere more than in the media.

None of this is news to our readers – but the Leveson inquiry evidence so forensically laid out by Robert Jay QC sets out the shameful tale for all to see. Murdoch's replies will enter the annals of amnesia and economy with the truth: "I've never asked a prime minister for anything in my life." Of course not. He just breathed on them.

Is there anything so exceptional about Rupert Murdoch? He's canny and fly, but probably no more so than many sharp-witted businessmen who spot their chance in a flabby market. All he has done is exactly what Adam Smith (the real one) famously said every businessman does given half a chance – corner markets and conspire against the consumer. The success of his business was built on gaining the edge by evading regulators and avoiding taxes, as all companies will unless stopped. So let's not obsess over his character.

If you think this is a navel-gazing media story, here's a reminder of what Hunt was about to unleash on the country, with Cameron and George Osborne's approval. If Murdoch were allowed to own all BSkyB, within a year or two he would package all his newspapers on subscription or online together with his movie and sports channels in offers consumers could hardly refuse, at loss-leading prices. Other news providers, including this one, would be driven out, or reduced to a husk. His would be the commanding news voice. Except for the BBC – which his media have attacked relentlessly for years.

Sky's dominance over the BBC is already looming: now past its investment phase, Sky's income is multiplying fast at £5.5bn a year, against the BBC's static £3.5bn. Sky's growing billions can buy everything, not only sports and movies, but every best series: the BBC trains and develops talent, predatory Sky will snatch it.

The BBC is remarkable value for money: Sky subscribers can pay £500 a year, the licence fee is £145 for masses more content. Sky is parasitic, as its own subscribers watch many more hours of BBC than Sky, so Sky would collapse if the BBC denied it its channels. Yet the BBC still pays £5m a year for appearing on its platform, a deal struck by Thatcher to help Murdoch.

The sum was cut, but in all other countries commercial broadcasters pay national broadcasters for the right to use their content – not the other way round. The BBC should be paid a hefty fee from BSkyB to compensate for the 16% cut it suffered, partly as a result of Murdoch lobbying. The cut was pure spite, since the licence fee has no connection with Treasury deficits. Pressure persists to deprive viewers of listed national events saved to watch free on BBC: Wimbledon and the rest would go the way of Premier League football.

If it does nothing else, this scandal will stop the government daring to give anything more to Sky. Much as the Tories detest the BBC – which, like the NHS – stands as a defiant symbol of non-market success, expect no overt attacks on it for a while now. But the BBC charter comes up for renewal in 2017: a Tory victory at the next election would liberate them to follow their vengeful instincts.

Jeremy Hunt was within days of giving Murdoch everything, because the government wished it. A token gesture would have put Sky News behind Chinese walls, but on all previous precedent, soon his newspapers, print, online and TV would have merged into a single newsroom. That would require repeal of the law imposing impartiality on broadcasters. But already Murdoch's friends were softening up opinion against old-fashioned, dull TV news, unsuited to the rowdy, opinionated internet era: Fox News would soon be here. If the arrival of Murdoch's kick-arse Sun was a shock, we'd look back on it as an age of innocence compared with what Fox would do – look what it's done to US politics.

Cameron has said it is his ambition to finish Margaret Thatcher's work. As she privatised nationalised industries, so he would marketise the public sector, with his NHS commercialisation and his promise to put all public services out to tender. The dismantling or shrivelling of the BBC would soon have followed. If Nick Davies had not exposed the hacking of Milly Dowler's phone in the nick of time, all would have been lost – an odd way for the BBC to be reprieved.

The 81-year-old under scrutiny this week rambled a bit and remembered nothing to his own detriment. He was an unsatisfying villain, as most are. But the villainy here is not about one man. He stands as an Adam Smith lesson in the primacy of competition law and what happens when politicians let the free market rip to do political favours.

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• This article was amended on 1 May 2012 to delete an incorrect statement that for every £1 in Sky subscriptions, 90p goes straight to News Corp and Hollywood in the US.