What i believe is that there is more to just following in your fathers foots steps. If you had just been exactly like your father you would never have gotten [censored] done for yourself in the wasteland. The game shows in its own way the even when humanity has succeeded in destroying everything it held dear and driven off from a clear path it can be given a second chance to start anew and learn from its mistakes. That is why The Lone Wanderer goes up and beyond his father to make sure humanity gets this chance.
Except we don't know to what extent of what "chance" is given to "humanity" as a result of the LW so-called courageous deed.
You say humanity but in reality we are talking about the people of the Capital Wasteland. The only time humanity is ever mentioned is when the narrator gives us background information or talking about humanity as whole.
Okay, fresh water is important but...so? The only thing that affects the Capital Wastelanders is that they can have fresh water.
And?
What happens to Canterbury Commons? Does the LW give them the money to combine the caravans so that more profit can come to town? Did they establish decent trade relations with other towns like the Go-To-Lucky Caravans or the the Crimson Caravan in the NCR? Did they become the trading center for the Capital Wasteland?
What happens to Arefu? Did they get the bodyguards? Did they move away? Were they decimated?
What about Rivet City? Do they betray the BOS because of all the stress they have delivering fresh water throughout the Wasteland? Did Rivet city began a sort of expansion? Do they want to control the purifier? Do they establish a sort of "nationality" that could develop into some sort of body of government?
What happens to the Vault 101 Dwellers? Did they live? Did they die? If the vault is open, are they prospering? Or were they doom to fail anyway?
How about the Reilly's Rangers, the Underworld with their Ghouls, Galaxy News Radio, the BOS, Vault 87, your followers, and so on and so forth. What became of them?
See, THESE are what should have been given to us, not if the LW succumbed to the vices or not. The LW is not "humanity" and he is also does not speak for the entire populaton of the Capital Wasteland.
However, to be blunt most of the towns were just plain awful and didn't provide a story and purpose. What sort of economy did they have? How did they sustain themselves? Did they have some sort of connections with other towns? I find it ridiculous that everything they ever got is scavenged. Even with fresh water provided to them it won't change anything. They still will be a bunch of mindless idiots with their tail between their legs.
So tell me, what good will come to these Wastelanders as a result of having "fresh water" provided by the LW's due to his noble deed?