I think the creator and writer of The Wire based the characters and plot in his experience as a journalist working for Baltimore Sun. Some characters are less fictional than others, but I think he wanted to depict and emphasize how the city works. So maybe not too far from the real Baltimore.

I think while some characters are plain shit persons, many characters have a lot of depth in them, making you feel and root for them despite being the “bad guys”.

It also shows that doing what would be considered “right” will not always work out for you.