When a leader loses power, their followers become disorganised and often lose faith in the cause. The following phrase is now used to refer to people who ditch a lost cause because they weren't committed to it. The creators of a cause would however try and keep the cause afloat whereas the followers just there for the ride would just ditch it.

This proverb is likely to be used to describe fair weather friends, although in both cases is applicable.

More often in English, this proverbs meaning would be conveyed in the following proverb: