The "golden age of television" cited by Kevin Spacey at the Guardian Edinburgh International Television Festival is defined by flawed characters and multi-stranded plots. But the actor's presence at the industry conference late last week was uncomplicated in its starriness. His keynote address had a simple, singular message: trust "the talent", because in the long run they will make you money.

Taking risks and submitting to what his acting mentor Jack Lemmon called "a sense of total abandon" will keep traditional broadcasters in the game at a time when they face increasing competition from Netflix, YouTube and other "television" content that no viewer has ever had to tune in or fiddle with an aerial to watch.

Spacey was invited to the annual event, which was attended by more than a thousand industry professionals including representatives of RTÉ, TV3, the Irish Film Board and several Irish production companies, because as the lead actor in Netflix's first original production, House of Cards, he has become the face of the streaming service. The cut-throat political drama opens with a scene in which Spacey's "diabolical" character strangles a dog.

For Spacey, a good deal of the joy of working with Netflix revolved around its willingness to commission 26 episodes of House of Cards without the need for a pilot - not only did Spacey and producer-director David Fincher not have to make a 45-minute audition, but there was no need for head writer Beau Willimon to follow the typical pilot format of setting up the full cast of characters and ending on "arbitrary cliffhangers" in episode one.

Rather than having the guts to say "we like this idea", the US industry spends $300-$400 million every year on pilot season, with only a small percentage of shows progressing to a full series - some 35 of 113 pilots were commissioned last year, and only 13 have been renewed for this season. Too bad if those that fell by the wayside were Breaking Bad-style slow burners that needed time to find their audience.

Though not anywhere near as embedded here, this US tradition has recently become more common on this side of the Atlantic - a fact TV3 hopes to exploit by inviting UK companies to shoot pilots for competitive rates in its new HD studio.

Spacey surmised that a more nervous, pilot-seeking funder than Netflix might have said “umm, we are very concerned about the fact that Kevin strangles a dog in the first five minutes of the show” - and yet that scene “set the tone for the entire series”.

His characterisation of television executives as interfering types who only water down creative visions didn't prevent him from receiving a standing ovation from a crowd populated largely by commissioning executives, “money people” and other “suits”.

Listing a creamy crop of US dramas beginning chronologically with The Sopranos and ending with House of Cards, Spacey said the challenge now was "to keep the flame of this revolutionary programming alive by continuing to seek out new talent" and give it autonomy. He was "disappointed" by laziness and complacency, he said. "I don't think we do enough."

Wearing a zip-up oatmeal cardigan with upturned collar in the classic Hollywood style, Spacey participated in a question-and-answer session on Friday morning in which he implored executives employed as de facto talent-spotters to go watch theatre performed in basement theatres and investigate the undiscovered storytellers performing comedy over on the other side of town at the Edinburgh fringe.

He also backed the idea - typically regarded as uneconomical by the creative industries - that giving people permission to fail is the path to their success. The writers' room of The Sopranos had individually produced "a lot of crap" before they struck mafia gold, he said. "But they had paid their dues and they were learning."

Not everyone was ready to give Netflix all the plaudits for their creative originality. House of Cards, as Dara O'Briain joked to the conference, is, ultimately, a US remake of a BBC drama (in turn adapted from a Michael Dobbs novel) that ran in the early 1990s. It introduced the phrase "you might think that, I couldn't possibly comment" to the political lexicon back in the era of VHS.

More pertinently, investors in media companies don't always back Spacey's assertion that "the risk-takers are rewarded". In the first quarter, House of Cards buzz helped Netflix gain 3 million subscribers. But in the second, the addition of 1.2 million new subscribers fell short of the high expectations of Wall Street analysts wary that its original content strategy could go wrong at any time.

Now boasting almost 38 million subscribers, including 1.5 million in the UK and Ireland, Netflix has proven itself as the global player most willing to take expensive risks in 2013 - even ones that are mitigated by being fronted by big names. But that doesn’t mean the consequences of failure won’t cast a shadow over its creative confidence in future, just as it does for older broadcasters with shrinking piles of cash to burn.