From the 1950s through the 1970s, a band a musicians — some of whom became famous solo acts — were responsible for an incredible number of the pop hits that became successful.
If you are at all interested in musical history, you'll appreciate this:
en.wikipedia.org
Note that even self-contained bands, such as the Beach Boys, would rely on the Wrecking Crew to do their studio backup tracks because they were fast, creative, and thus kept the studio bills low.
If you are at all interested in musical history, you'll appreciate this:

The Wrecking Crew (music) - Wikipedia
Note that even self-contained bands, such as the Beach Boys, would rely on the Wrecking Crew to do their studio backup tracks because they were fast, creative, and thus kept the studio bills low.