How will HBO fill the void left by 'Game of Thrones'?

HBO didn't used to be all about Game of Thrones.

Home Box Office, to give it its full though rarely used title, has been going since the early 70s as a cable service in the US.

Then in the early 90s, it hit upon a seam of underground hits in its original programming – shows like Tales from the Crypt, Marta Kauffman and David Crane's Dream On (they'd go on to make Friends), Mr. Show and the magnificent Larry Sanders Show.

In the latter part of the decade and into the millennium, things really began to hot up, with acclaimed prison drama Oz, and then in 1999, The Sopranos. Then The Wire, Deadwood, Band of Brothers, The Pacific, Sex and The City, Six Feet Under and True Blood.

They were shows any network would have given their shirts for.

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But when Game of Thrones came along, helmed by novice showrunners David Benioff and D.B. Weiss and adapted from George R.R. Martin’s best-selling fantasy novels, things went stratospheric.

It's attracted viewership beyond anything it could have predicted. In fact, HBO doesn't even know how many people will have ended up watching this final season of the show, due to the numerous platforms it appears on around the world – on Sky Atlantic, and via Now TV in the UK.

It's shown in 170 countries, with Entertainment Weekly reckoning on 100 million viewers (season seven averaged nearly 33 million per episode).

But now it's gone... what next? Forbes – quoting a poll from Mintel – reports that it's possible that 20 percent of the eight million subscribers in the US are mulling cancelling their HBO subscription now the show is over, particularly now that there's a far more crowded marketplace than when Thrones started in 2010.

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Netflix has continued to grow, along with Amazon Prime, and new services like Apple TV+ and Disney+ are just waiting in the wings to take another bite.

There is a Game of Thrones prequel spin-off show planned – with British Kingsman and X-Men scribe Jane Goldman writing it – but it won't arrive for quite some time yet, so what will HBO be able to do to stop the potential stream of deserters?

Westworld will be coming back in 2020, and though that's some way away, HBO is clearly aware of this, releasing its first look at season three last night.

It's bringing in Breaking Bad's Aaron Paul to star in a season which co-showrunner Lisa Joy has said will be 'very different' to the previous two seasons (though it's worth noting that, even though Westworld is HBO's second biggest show, Game of Thrones gets three times its audience).

The Deadwood movie will arrive at the end of May too, harking back to one of the channel's first big hits.

But elsewhere, there's the new Watchmen series, based on the revered comic book by Alan Moore and Dave Gibbons, being show-run by Lost and The Leftovers creator Damon Lindelof, and starring Regina King, Don Johnson and Jeremy Irons.

And in what looks to be a lavish co-production between HBO and the BBC, there will be His Dark Materials.

Based on Philip Pullman's much-loved books, it will find Logan star Dafne Keen as Lyra Belaqcua, a young girl at the centre of a prophesy in an alternate universe where witches pierce the skies and armoured bears roam the north.

It stars Ruth Wilson, James McAvoy, Clarke Peters, James Cosmo and Lin-Manuel Miranda, and is set to premiere later this year.

There's also The New Pope, with Jude Law and John Malkovitch coming later this year too, continuing the series The Young Pope from 2016, with Law reprising his role as Pope Pius XIII.

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Benioff and Weiss, even though they're now working on a movie in the Star Wars series, were also attached to run new HBO drama Confederate last year, set in an alternate reality in which the American Civil War ended in stalemate, and slavery remained legal in southern states, building towards a new conflict.

However, there was huge backlash against the idea, many dubbing the idea tone deaf, and 'slavery porn', though in February this year, HBO president Casey Bloys said it was still in development.

Whether this is enough to keep people paying for HBO remains to be seen.

Plenty of other networks are gunning for the HBO viewership too, notably Amazon producing its big-budget Lord of the Rings series in the hope of specifically grabbing those Thrones viewers.

Meanwhile, the memes are already out there...