For additional information, here is a good description of this type of music (taken from Wikipedia:
"Género chico (literally, "little genre") is a Spanish genre of short light musical plays. It is a subgenre of Zarzuela, the Spanish operetta. It differs from Zarzuela grande and most other opera forms both by being short and by aiming at a proletarian audience."
For a complete article on Zarzuela and its subgenres, see:
http://en.wikipedia.org/wiki/G%C3%A9nero_chico
It is also interesting to note how political and economic circumstances could have an important impact on the type of works produced and the ways of attending performances.
This reminds me the current revolution on Internet, concerning the legal, para-legal and illegal distribution of music through the widespread use of mp3 formats.