Word/ expression/ idiom for "when you realize the good deeds someone has done after their departure/ death"

Oftentimes there are people that do good and people don't respect them (and/or rebuke them), but when they leave the place or die, people realize that they were a good person and that what they did was great and good.

Examples:

1. There was an employee (A) in a shop who used to keep the shop organized and tidy but the owner of the shop wouldn't respect it and would rebuke him. After A left the job and the owner assigned his job to someone else B, the B wasn't so organized and the shop would always be messed up, the owner realized that the first employee A was much better and what he did was good and he was a nice employee.

2. Sometimes there are wise people that people don't respect much but when they die, people realize how kind and wise they were.

Is there an idiom in English to convey/express that?

Edit: I am not sure as to how my question lacks details. I have provided two examples and have explained the situation. Can the close-voters explain how else could I explain and clarify my question?

How about you don't know what you've got till it's gone?

You don't fully appreciate people or things until you lose them.

My grandfather passed away last month, and I miss him so much. Truly, you never know what you've got till it's gone.

Farlex

See also the song Big Yellow Taxi (1970), which seems to be the origin of this expression (if not, it's what popularized it).

If context includes death, posthumous recognition can be a good fit.

"posthumous"

• "occurring or continuing after one's death"¹

• "following or occurring after death"²

If the dead one reaches world-wide recognition and admiration, such as Van Gogh, Emily Dickinson or Allan Poe, you can use "posthumous fame"

If the recipient has only quit, you may well use one of several sayings such as "you only realize the importance of someone when they are gone" or "you never know the value of a person until they're gone"

distance lends enchantment (to the view) proverb

When one is removed from something, it becomes deceptively appealing.

But you hated that rickety old house when we lived there! Remember that distance lends enchantment to the view.

[The Free Dictionary]