While podcasts don’t seem poised to overtake TV in sheer hours watched (Netflix still accounts for a full third of all internet activity), they do have a healthy core audience, which means they could theoretically sustain a Netflix model. Here are the companies hoping to become the Netflix of podcasts and what the big barrier they face is.

The Contenders

There are three main contenders in the battle for all-you-can-hear podcast supremacy. E.W. Scripps bought the podcast app Stitcher for $4.5 million last June, and they’re already calling their new Stitcher Premium service the “Netflix of podcasts.” Howl, created by Midroll Media (which is also owned by Scripps) has been called the exact same thing. Meanwhile, Audible’s subscription podcast business Channels came out of beta last July, and guess what it’s being cited as? Unlike music, which has a clear winner in Spotify, the podcast version of Netflix is yet uncrowned. So why is there so much activity in this specific field?

The Benefits: An Engaged and Growing Audience

In 2017, with social media platforms cracking down on weak posts harder than ever, an engaged audience is essential. I’ve called 2017 the year of the audience. Others have called it the year of the social influencer. But our point is the same: Any publisher or platform that has cultivated a genuinely invested audience will be increasingly successful in the years to come. Podcasts are doing well for themselves, as this summary of Infinite Dial’s annual report explains: Like books, podcasts remain a cheap medium to produce in comparison to TV. Unlike books, they have a healthy and growing audience.

The Barrier: Getting People to Pay

The podcast news service Hot Pod recently offered a great breakdown of the biggest challenges facing a service that hopes to capture as large a podcast market as Netflix has captured the streaming video market: In the end, it’s possible that the lucrative ad money found in podcasts thanks to their strong niche audiences (a podcast with 200,000 listeners should earn at least $1 million a year, according to Pineapple Street Media co-founder Jenna Weiss-Berman) will remain the dominant revenue stream for podcasters. A Netflix of podcasts might be a sustainable model, but podcast ads are probably a better one.