I don't think this holds to scrutiny. This breaks down as soon as you get out of the idea phase.
Everyone has visions, and most great achievements today are the results of an amalgamation of them. The really big achievements are almost always the result of groups, not individuals.
People that idolize others have to turn a blind eye to everything surrounding that individual's achievement. It's simply easier to simplify big achievements as "this person was great". In reality though, it's a culmination of everything that came before that individual, the support around them, some of their decisions and much more.
In other words: monuments are a bad argument to evaluate if something is good or not. Especially in today's individualistic society.
It's a shallow Instagram motivational phrase.