When Verizon introduced its internet TV service Go90 in September 2015, it promised to reinvent the TV model. But not even three years later, Verizon is shuttering the service, which failed to gain traction with either viewers or advertisers.

Go90 debuted to much hype and a vague plan "to challenge the fundamentals of the industry," as Brian Angiolet, senior VP, chief content officer at Verizon, put it to Ad Age in 2015.

Before the service even went live, it received over $50 million in ad commitments, including a deal with Publicis that included more than 10 of the agency's clients. But Verizon ultimately struggled to meet its audience deliveries.

Its experience demonstrated the perhaps-obvious reality that you can't reinvent the ad model without large scale and wide distribution. Or maybe you can, but marketers won't buy the ads.

Verizon did not respond Friday to questions about the number of paying Go90 subscribers.

Go90 included a mix of live events, existing prime-time TV shows and original series, including Kobe Bryant's Oscar-nominated animated film "Dear Basketball." Angiolet said at the time that all of this content living side-by-side would shift the way ad inventory is valued.

There was also the promise of one-to-one targeting of consumers and plans to revamp video ad units for a mobile viewing experience, rather than just repurposing TV spots. Before YouTube popularized the notion of six-second ads, Go90 executives talked up commercials that would run five to seven seconds.

With Go90, so named on the premise that people turn their phones horizontally to watch longer video, Verizon became an earlier mover into what has since become a crowded market for over-the-top video—video that skips over the traditional cable and satellite boxes to reach consumers. Go90 was subsequently overshadowed by similar services from YouTube and others, as well as video efforts by social platforms like Snapchat and Instagram.

And in a reflection of the ascent of vertical video since Go90 came around, both Snapchat Shows and Instagram TV expect viewers to hold their phones upright throughout even longer content.

Verizon now plans to focus "on building its digital-first brands at scale in sports, finance, news and entertainment for today's mobile consumers and tomorrow's 5G applications," the company said in a statement.

Oath, the media and advertising unit that includes AOL and Yahoo's online products, will serve as the home for Verizon's video efforts.