The branding involves a lot of ingredients.
On a top level:
Someone above just said escapism.
Tropics
Vacation
Drinking
Cuban, Hispanic influences - music and drinks
Margaritas obviously, and he popularized them
Island influences - steel drums for example
Visuals - warm climates, shorts, Hawaiian shirts
Sailing, boating
etc. drugs?
etc.
Then add meaningful, understandable, relatable songs and stories.
The above just scratches the topic a little and are my initial thoughts. Feel free to add.
But a few years ago when Wheel of Fortune started having “Margaritaville Week”, I did ask myself, WTF? Hotels, vacation properties? These people have taken this a LONG way from smoking weed in a concert parking lot.