Derogatory reference to the 80s blues-rock group; meaning to lower in quality or be of exceedingly low stature. Example: Sheryl Crow used to be cool. It's sad to see her go all Fabulous Thunderbirds these days.
FABULOUS THUNDERBIRDS
Meaning of FABULOUS THUNDERBIRDS in English
Slang English vocab. Английский сленговый словарь. 2012