Talking at the PPA conference today, Brooks opened with a "brutally honest assessment" of the state the industry now finds itself, noting that its ad share had slipped by 16% since 2007.
He used the latest figures from UKOM to highlight the battle traditional magazine publishers now face to stay relevant in the digital age.
He said last month's aggregated audience of the top 20 selling magazines in the UK totalled 4.2 million people, compared to 5.2 million people for The Guardian alone.
Brooks, who was a magazine publisher for 25 years including senior roles at IPC and Emap, noted in contrast that both advertisers and consumers were shifting very rapidly from print to digital.
He added: "I don't really think this is a battle for consumers' money, but much more importantly it's a battle for consumers' time."
He said "in future there will be fewer magazines" and the brands that survive will be multi-platform.
The managing director's reach argument continues the ‘chasing of eyeballs' philosophy that has seen the Guardian become the second-largest English-language newspaper in the world, despite being only the eighth largest, in terms of print circulation, in the country.
Later in the session he predicted that News Corporation's strategy to erect paywalls would make The Times' website a "very lonely place".
He called the move instigated by Rupert Murdoch "a strategy to defend his print subscriptions" although he refused to rule out the Guardian ever adopting the approach if commerciallly successful.
Brooks said: "We believe in charging consumers in places where they are happy to pay. Those places are WH Smiths and the iTunes store. They are very unhappy to pay on the internet."
While recognising the ability magazines have to bring people and communities together, he warned that "digital is not constrained by frequency".
He concluded his presentation by urging magazine publishers to ask four fundamental questions about their current business for future survival.
He said: "Do we have the digital talent that we need? Does that talent have a strong enough voice? Do you have the organisational appetite for profound and ceaseless change, because that's the future, and, finally, do you have the humility to recognise the strength that you face in the digital environment?"
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