ABBA

Context: In March 1976, the band released the compilation album Greatest Hits, despite having had only six top 40 hits in the United Kingdom and the United States. Nevertheless, it became their first UK number-one album, and also took ABBA into the Top 50 on the US album charts for the first time, eventually selling more than a million copies there. At the same time, Germany released a compilation named The Very Best of ABBA, also becoming a number-one album there whereas the Greatest Hits compilation followed a few months later to number-two on the German charts, despite all similarities with The Very Best album. Also included on Greatest Hits was a new single, "Fernando", which went to number-one in at least thirteen countries worldwide, including the United Kingdom, Germany and Australia, and the single went on to sell over 10 million copies worldwide. In Australia, the song occupied the top position for 14 weeks (and stayed in the chart for 40 weeks), tying with the Beatles' "Hey Jude" for longest-running number-one, and making "Fernando" one of the best-selling singles of all time in Australia. That same year, the group received its first international prize, with "Fernando" being chosen as the "Best Studio Recording of 1975". In the United States, "Fernando" reached the Top 10 of the Cashbox Top 100 singles chart and number 13 on the Billboard Hot 100. It also topped the Billboard Adult Contemporary chart, ABBA's first American number-one single on any chart.  The group's fourth studio album, Arrival, a number-one best-seller in Europe and Australia, represented a new level of accomplishment in both songwriting and studio work, prompting rave reviews from more rock-oriented UK music weeklies such as Melody Maker and New Musical Express, and mostly appreciative notices from US critics. Hit after hit flowed from Arrival: "Money, Money, Money", another number-one in Germany and Australia, and "Knowing Me, Knowing You", ABBA's sixth consecutive German number-one as well as another UK number-one. The real sensation was "Dancing Queen", not only topping the charts in loyal markets the UK, Germany and Australia, but also reaching number-one in the United States. In South Africa, ABBA had astounding success with "Fernando", "Dancing Queen" and "Knowing Me, Knowing You" being among the top 20 best-selling singles for 1976-77. In 1977, Arrival was nominated for the inaugural BRIT Award in the category "Best International Album of the Year". By this time ABBA were popular in the United Kingdom, most of Western Europe, Australia and New Zealand. In Frida - The DVD, Lyngstad explains how she and Faltskog developed as singers, as ABBA's recordings grew more complex over the years.  The band's popularity in the United States would remain on a comparatively smaller scale, and "Dancing Queen" became the only Billboard Hot 100 number-one single ABBA had there (they did, however, get three more singles to the number-one position on other Billboard charts, including Billboard Adult Contemporary and Hot Dance Club Play). Nevertheless, Arrival finally became a true breakthrough release for ABBA on the US album market where it peaked at number 20 on the Billboard 200 chart and was certified gold by RIAA. CANNOTANSWER

Question: why was ABBA's popularity in the United States smaller than i  the UK, Germany and Australia?
Answer: CANNOTANSWER