There are no dragons in “Vinyl.” While the lead character engaged in plenty of fiery outbursts, there was no steam coming out of his nose, although there was a lot of powder snorted up it. But it is the kind of gaudy, expensive item that seemingly only HBO could mount, and with the Martin Scorsese-Mick Jagger-Terence Winter collaboration having just wrapped up its season and “Game of Thrones” about to return, it’s a pretty good reminder of how enormous those shoes will be to fill – and that even loading up the scales with A-list talent offers no assurance of success.

HBO asked that those who attended the “Thrones” Season 6 premiere not spoil anything, which is admirable. It gives nothing away, however, to say the more-eventful-than-usual opening is characteristically gorgeous, spanning multiple locales and juggling a dizzying assortment of plots. Although the show waited until last year to win an overdue best-drama Emmy, nothing on TV has quite rivaled its feature-scale ambitions, and that’s clearly not going to change as it heads into the home stretch of its epic run.

That term – “home stretch,” with two more, perhaps truncated seasons in the offing – has added an element of urgency to HBO’s development efforts. Just as the network was being second-guessed when “The Sopranos” cut to black – what could ever be that huge again? – the combination of development misfires and “Thrones’” cultural clout has left naysayers muttering about whether bidding farewell to those “Winter is Coming” billboards will trigger the pay-cable equivalent of an ice age.

“Vinyl,” of course, was just one of the projects introduced as HBO prepares for life beyond Westeros, but it certainly came with the kind of pedigree that couldn’t be ignored. Not only did it reunite “Boardwalk Empire’s” creative heavyweights and actor Bobby Cannavale, but Jagger’s insight into the ‘70s music scene – complete with all the expensive song rights that required – marked this as a premium item in more ways than one.

But then the show premiered, to less-than-completely-glowing reviews, and a relatively modest audience showed up. The episodes remained watchable but didn’t improve from the messy two-hour premiere, testing the limits of how many times one could watch Cannavale inhale a huge line of cocaine and toss his head back with wild-eyed abandon.

HBO almost immediately renewed the series anyway, essentially declaring victory in the first quarter. After that, though, another major shoe dropped, with the announcement that “Vinyl” showrunner Winter would be leaving. Suddenly, what looked like a can’t-miss headliner appears destined for the TV equivalent of a hotel lounge.

Anyone hoping the finale might provide the foundation for a fresh start was likely to be disappointed. While the episode (and SPOILER ALERT if you haven’t watched) added to the rift between the characters played by Cannavale and Ray Romano (who has been a bright spot among the cast), the subplot involving the record company’s involvement with the mob seems tired, as did the “Singer ODs right before big show” moment. “Vinyl” conjured some interesting beats, but too often its run-ins with artists from the era felt like the historical-drama-series version of name-dropping.

Yet if the anticipation for the series turned out to be overstated – further proof that marquee names provide no guarantees – the temptation to write epitaphs or “HBO in trouble” pieces is equally premature. Because while the network has hit a rough patch – from canceling “Togetherness” to delaying “Westworld” – as noted, this is hardly the first time the channel has faced the challenge of reloading.

HBO still has an enviable war chest at its disposal, and offers plenty of prestige items, like this spring’s movies “Confirmation” and the upcoming “All the Way,” that no one else even tries to emulate. What the network needs isn’t necessarily another mass-appeal hit (although that obviously couldn’t hurt), but a few shows that feed the aura of creative supremacy that it so carefully cultivates.

As for the prospect of reinvigorating “Vinyl” to meet those objectives, it’s difficult to get second bites at the apple. Indeed, despite the critical praise heaped on the second season of “The Leftovers,” the audience largely responded with a shrug, and HBO’s decision to grant the show a third and final flight — as opposed to just letting it disappear — felt as much like a PR move as a programming one.

Juxtaposed with the ticking clock on “Thrones,” what “Vinyl’s” performance does mean, surely, is that the stakes have risen as HBO rolls out new programs between now and the moment when George R.R. Martin’s creation officially signs off. And while the seat of power at HBO seat isn’t as precarious as the Iron Throne, if there are many more “Vinyls” on the playlist, it’s going to start gradually feeling hotter.