Look at all the calculations you had to do to reach the max.
Getting to the unhappiness cap requires knowing the exact minimum dimensions of each house, and exactly how to arrange them to get every NPC within the range. And that only applies to the one NPC you reached the cap on...
Um, if you follow along with the calculations, virtually every NPC in that block has max unhappiness.
You act as if this example were artificial, that I was designing a hypothetical structure for the purpose of maximizing unhappiness, rather than merely describing the
exact housing I built in 1.3. This is not a hypothetical example; this is what I have done for many years, and it is what is most convenient for me to work with.
My overall point is that building in a way that maximizes user convenience applies an arbitrary penalty across the board.
Except it isn't, spreading out NPCs gives you access to pylons. The convenience of having cross map teleportations far exceeds being able to put everyone in as small a space as possible.
Happiness has nothing to do with Pylons; by Hardmode, you'll have more NPCs than you need to power Pylons. It isn't the presence of Pylons that makes you spread NPCs out; it's the unhappiness that builds up when you keep them close that makes you spread them.
If Pylons existed and happiness did not, I would have the Goblin Tinkerer and the Mechanic in my base, rather than stuck underground behind a Pylon teleport. The NPCs I would be spreading out would be those I don't use, and I'd be sending them away specifically to power Pylons, not because it'd give me lower prices. In short, I would have a
choice about who to keep and who not to.
Do not confuse happiness and Pylons; as much as the developers want to combine the two, they are distinct mechanics.
Also, you're straying slightly from the subject of the post. This isn't a thread about whether the NPC happiness mechanic is a good mechanic. This thread is about the narrative of the developers wanting to control how players play the game, to discourage certain behaviors and encourage others arbitrarily.
My overall point is that this narrative is false,
however, you cannot deny that the happiness mechanic follows this narrative to a T. The developers
themselves stated that the primary purpose of it is to encourage you to spread NPCs out more, and discourage you from building close housing projects.
The narrative exists because happiness is exactly that kind of mechanic. All of the other evidence for the narrative is largely wrong, but happiness is exactly that kind of thing. The developers said it was, the design of the mechanic is incredibly arbitrary and overly controlling, and it strongly punishes the default method of building housing.