Grid frameworks like 960gs never became as popular as Bootstrap because Boostrap is as much about formatting content (including forms and UI elements) as it is

Grid frameworks like 960gs never became as popular as Bootstrap because Boostrap is as much about formatting content (including forms and UI elements) as it is about the responsive grid layout. I suppose you could say it comes with a theme, but anyone who cares enough to complain about the theme should also be motivated enough to customize it.