Conversation so far:
What group of Frank Zappa's disbanded?
Frank Zappa and the Mothers of Invention disbanded in 1969.
When did The Mothers of Invention disband?
Frank Zappa and the Mothers of Invention disbanded in 1969.
What kind of music did The Mothers of Invention play?
Their sound mixed R&B, doo-wop, musique concrète, and experimental sound collages that captured the freak subculture of Los Angeles at that time.
Why did The Mothers of Invention break up?
Frank Zappa often cited financial strain as the main reason, but also commented on the band members' lack of sufficient effort.

Question: Why were there financial problems?
Self-contained rewrite: Why were there financial problems for The Mothers of Invention ?