Conversation so far:
What group disbanded?
Zappa and the Mothers of Invention.
When did they disband?
In late 1969, Zappa broke up the band.
What kind of music did they play?
major influence on the development of the jazz-rock fusion genre.
Why did they break up?
He often cited the financial strain as the main reason, but also commented on the band members' lack of sufficient effort.
Why were there financial problems?
Zappa was supporting the group himself from his publishing royalties whether they played or not.

Question: why did he think the band lacked effort?
Self-contained rewrite: why did Frank Zappa think the band lacked effort?