In the nearly 20 years since British-born "Now That's What I Call Music!" series began selling compilation CDs in the U.S., competition has gotten fierce. Streaming services such as Spotify and Pandora compile their own playlists for listeners, often automatically and instantly. Nobody has needed Now Music, in the U.S. a joint venture between Universal Music Group and Sony Music Entertainment, to scrape hits from longer records since iTunes started selling 99-cent downloads.

As a result, "Now That's What I Call Music 65" sold only 25,000 physical and digital copies in its first week this February, down from 525,000 debut-week sales for "Now That's What I Call Music 6"—the 2001 album that included the 'NSync smash hit.

While the same trends have affected the entire industry, Justin Timberlake's "Man of the Woods," by comparison, sold 242,000 copies during its first week this February.

Yet Now is knee-deep in planning both a release marking its 20th anniversary this year and its first concert series. It still enjoys good placement in stores like Target and Walmart, and its albums typically sell 250,000 copies over time—80 percent in the form of physical CDs—good for more than 1.5 million record sales a year. The brand's peak year was 2001, when its seventh edition sold 621,000 copies its first week. Now wouldn't comment on whether it is currently profitable.

"How is it that a fast-food cheeseburger is still around when you can get a fancy gourmet cheeseburger?" says Charlie Harding, co-host of "Switched on Pop," a podcast about the making and meaning of popular music. "People still want a Big Mac. ... There's nothing wrong with that."

Perhaps more important, finding lists that play the hits is harder than you think, Harding adds. "My Spotify algorithms have not been serving me very well lately," he says, citing their tendency to surface little-known songs and artists. "I joke that everything sounds like a Jetta commercial."

Now Music provides a tightly edited mirror of pop culture—mixing big songs from streaming and radio with songs that will take off in a few months and the requisite "smash hits." Some of it comes from monitoring metrics and various data streams. Some is intuition, says Jeff Moskow, a former DJ who has produced all of Now's releases since 2000. He acknowledges there have been missteps here and there. "Do we get it right all the time? Of course not, nobody does."

"You can have 30 to 40 million songs, depending on which service you're following, but there's difficulty trying to find what you want to listen to," says Jerry Cohen, chief operating officer at Now Music.

"We like to say that Now is the original playlister," says Moskow. (It also posts playlists on the streaming platforms, saying consumers want a "Now"-branded album or playlist.)

"The brand has a sound," Cohen adds. "It's really about taking the listeners on a journey. There's sort of a flow in our brand," which is crucial when its mixes can include Pitbull, Idina Menzel and Luke Bryan in one CD ("Now That's What I Call Music 51"). You can "put it on, enjoy it for an hour and 20 minutes, and go, 'Wow, that was quite a ride.' "

The brand also arguably has a core consumer: people who don't know exactly what they like, who don't spend hours reading music blogs, who—to put it bluntly—perhaps don't have strong taste in music.

Josh Rabinowitz, senior VP and director of music for Grey Group, likens Now to Old Faithful. "There are still a lot of people who buy CDs—not as many, obviously, as before," he says. "This is something that people have been comfortable with for years."

Now is "comfort food" for that demographic, Rabinowitz adds. "The brand has maintained a loyalty and success because the curation has been spot-on, the musical choices have remained current, and that has helped it keep its fan base and brand intact. It's a reliable fixture and to many a great listening experience."

Moskow says he believes the Now brand has grown beyond that fan base. He sees a portion of its buyers as "typical American families" who might drive a 7-year-old car with a CD player but not Bluetooth streaming, and appreciate Now's clean radio edits. " 'Now' fills many needs," he says, "but definitely fills that 'Let me just pop it into the dash and not have to worry.' "

Once upon a time, Now marketed its albums with 1-800 radio-announcer-voiced commercials. Today it puts most of its marketing budget online.

Cohen says some fans are nostalgic for the brand. Some are collectors of the physical albums or boxed sets. And some are impulse buyers who pick up the CDs at Target or Walmart.

Beginning April 16, fans will be able to vote online for the tracks that will appear on "Now's 20th Anniversary" album, due out this fall. Also planned: a showcase concert series, which the brand hasn't done before. Now Music is working with Capitol Records to launch the first showcase in the fourth quarter.

Though Cohen says he's not sure Now will make it to "Now 500," the brand plans to do whatever it takes to keep up. "We still are looking for every way we can to make ourselves relevant in the streaming market," Cohen says.