When the new season of “Sunday Night Football” kicks off tonight — yes, on a Thursday — it will mark the 10th anniversary of the NBC franchise. But the more impressive milestone will likely come this spring.

Barring the unforeseen, “Sunday Night Football” will finish its sixth straight season as primetime’s most-watched show, tying “American Idol” for the most consecutive ratings crowns in history. The streak is a testament to the growing power of live sports at a time when viewing habits are evolving at a pace few in the industry anticipated. But the changes that made the current TV landscape fertile ground for the rise of “Sunday Night Football” are beginning to create uncertainties for sports broadcasters who had become used to watching their fortunes grow.

Since 2011-12, “Sunday Night Football” has led all of primetime television in the 18-49 demo and total viewers. In Nielsen numbers measuring live viewing plus seven days of playback, the distance between “Sunday Night Football” and primetime’s No. 2 show has been relatively consistent. But when looking at live-plus-same day numbers, the gulf widens over time in total viewers — from a 12% lead over the second place show in 2011-12 to a 28% lead last season.

Sports and live programming have, according to NBC Sports chairman Mark Lazarus, “maintained the need to watch it live” at a time when many viewers now wait days or even weeks to watch most shows.

“The value gap between [‘Sunday Night Football’ ratings] and other primetime programming has grown because people are consuming scripted or reality programming in different ways,” Lazarus said. “When you take two lines, one that stays steady and growing slightly and the other that goes down, that gap continues to grow.”

Although “Sunday Night Football” has dominated ratings for the last five seasons, it has done so on a plateau, with little up or down variation from year to year. But it reached its current perch after a period of steep growth. In its first season, the franchise didn’t even rank in broadcast’s top 10 in total viewers, trailing “House,” “Desperate Housewives” and “Dancing With the Stars,” among others, in live-plus-seven.

When NBC landed the NFL’s Sunday-night package, ABC’s “Monday Night Football” had for decades been football’s premiere primetime broadcast. The “Sunday Night” deal changed that. NBC would get the league’s best matchups. “Monday Night Football” would get punted to ABC’s cable cousin ESPN. To maximize the NFL’s biggest potential audience, NBC poached much of ABC’s “Monday Night” team, including executive producer Fred Gaudelli.

“At ABC it had gotten to the point where internally it appeared that it was something that wasn’t valued anymore,” Gaudelli said of “Monday Night Football.” “It was something that they were kind of letting die on the vine.”

In its last years on ABC, “Monday Night Football” ratings had begun to lag. According to Gaudelli, the network was most interested in the show “as a vehicle to promote other things,” rather than something to be nurtured and grown. But it still ranked among television’s highest-rated series, and maintained a cultural cache that NBC would be challenged to duplicate.

“It had such place in the American fabric that I thought ‘Sunday Night Football’ is going to be great, we’re going to have great games and all of that, but we’re probably not going to replace ‘Monday Night Football’ in the public’s conscious,” Gaudelli said. “And within four years we had done it.”

NBC’s approach to “Sunday Night Football” — “to do the game better than anyone and to surround it with all the pomp and all the celebration and all the glitz that would befit a primetime television show,” as Gaudelli described it — yielded ratings increases at a time when DVR penetration was on the rise, putting downward pressure on live-plus-same day ratings across TV. Now digital viewing is placing new pressures on sports broadcasters, who are struggling to adapt.

That struggle was on display as ratings poured in from NBC’s broadcast of the Rio Summer Olympics in July and August. NBCUniversal and parent Comcast invested heavily in efforts to make it easy for viewers to watch events online. Executives in both companies had predicted that digital streaming would drive viewers to linear broadcasts and yield record ratings. Instead, digital viewing exceeded all expectations while linear ratings fell short.

NBC owns streaming rights for “Sunday Night Football,” which will allow it to continue to monetize the franchise’s viewers as they migrate to non-linear platforms. But this season the network also joins a multi-network “Thursday Night Football” package that splits rights between NBC, CBS, NFL Network and Twitter, and at first glance looks perfectly designed to confuse viewers. CBS and NBC will each broadcast five “Thursday Night” games, each to be simulcast on NFL Network and Twitter. For NBC, the good news is that its ads will be played on the latter two platforms. The bad news is that those platforms will dilute viewing and depress the broadcaster’s ratings.

“We would prefer to have the whole ecosystem,” Lazarus said. “Most every other deal we have does that. This is a unique deal at a unique moment in time.”

That moment in time is one in which sports are television’s most valuable commodity and pro leagues — particularly the NFL — can practically dictate terms. For the 2016 “Thursday Night” package, NBC and CBS paid a combined $450 million, up from $300 million CBS alone paid just one year earlier.

But the unchecked growth in sports rights fees may run into the same stiff headwinds that have altered TV’s course elsewhere. Lazarus pointed to subscriber declines at ESPN — down roughly 10 million since 2013 — as an indicator of changes to come.

“We’re on a different growth trajectory,” Lazarus said. “But on the whole, we’re all susceptible to that same cord cutting, cord shaving, skinny bundle world. And I think that puts significant downward pressure on all of the video businesses, not just sports.”

But unlike other broadcasters confronting that pressure, Lazarus gets to do so with the most watched show on television in his arsenal.

“I think it’s going to be about how we keep score” in the future, Lazarus said. “I think you’re going to have as many people watching. They’re just going to be watching in various ways.”