Background: Van Halen is an American hard rock band formed in Pasadena, California, in 1972. From 1974 until 1985, the band consisted of guitarist Eddie Van Halen, vocalist David Lee Roth, drummer Alex Van Halen, and bassist Michael Anthony. The band went on to become major stars, and by the early 1980s they were one of the most successful rock acts of the time. 1984 was their most successful album.
Context: Van Halen's next lead singer was Gary Cherone, frontman of the then-defunct Boston-based band Extreme, a group which had enjoyed some popular success in the early 1990s. The result was the album Van Halen III. Many songs were longer and more experimental than Van Halen's earlier work. It was a notable contrast from their previous material, with more focus on ballads than traditional rock songs ("How Many Say I," with Eddie on vocals). Sales were poor by the band's standards, only reaching Gold certification, despite the album peaking at No. 4 on the U.S. charts. However, Van Halen III did produce the hit "Without You," and another album track, "Fire in the Hole," appeared on the Lethal Weapon 4 soundtrack. The album was followed by a tour. The III Tour saw Van Halen playing in new countries, including first ever visits to Australia and New Zealand.  Shortly afterwards, Van Halen returned to the studio and in early 1999, they started work on a new album. Working titles of songs included "Left for Dead," "River Wide," "Say Uncle," "You Wear it Well," "More Than Yesterday," "I Don't Miss You ... Much," "Love Divine," and "From Here, Where Do We Go?". The project was left unfinished when Cherone left the band amicably in November 1999. Citing musical differences, it is likely III's poor sales and critical reception had a big impact. None of the material from these sessions has ever been released, and in fact the band released no new material at all until three new songs were included on the 2004 Best of Both Worlds compilation. Lyrics that Cherone had written for the Van Halen III follow up would be used in his next project with Tribe of Judah.  Touring with Cherone had proven disappointing in terms of attendance. Eddie would later admit that "the powers that be" (Warner Bros.) had forced his hand in parting with Cherone. Unlike with the previous two singers, there was reportedly no bad blood behind the breakup, and Cherone remained in contact and on good terms with Van Halen. As when Hagar left, speculation resumed on a Roth reunion.
Question: Why were they so popular?. Whats the answer?
Sales were poor by the band's standards, only reaching Gold certification, despite the album peaking at No. 4 on the U.S. charts.