This feels like the torch luck situation all over again. It's arbitrary and tacked on all over another one of the dev's pet peeves. It's a sandbox game, people should be able to build and play it how they want, without being told 'no that's wrong' by a developer who will never even see their world, let alone play on it. Lots of people prefer having the NPCs in a centralized area. Maybe they like building big, elaborate cities. Maybe they just like having all the NPCs in quick, easy access. Maybe they just don't like the building aspect of the game and want to focus on the exploration and combat. Each of those reasons is just as valid as preferring many smaller scattered settlements, and shouldn't be arbitrarily punished by nonsensical price increases. Reason aside, it makes the NPCs feel like ingrates. Even if it just a shack, it's a solid four walls against the countless zombie hordes that appear every night. Not to mention the player rescues several of them from certain death in giant spider lairs or the depths of the dungeon or from literal damnation in hell.
Punishment aside, the happiness system feels incredibly bare bones too. Lazy really. It doesn't take into account any efforts made to make their homes look pretty, or thematically appropriate. The dryad is just as happy in a lifeless crude stone hut as she is in an elaborate living tree room with lots of flowers and life, as long as she is isolated and alone in the jungle. I personally enjoy making houses themed to each of the NPCs in a big city all together. It doesn't make sense that the NPCs wouldn't appreciate the effort went into making them a good home that would be to their liking. Ideally, a happiness situation should take into account what blocks and walls are used to make their home and what kind of furniture and decorations are used to furnish it, and reward players for taking the NPCs preferences into account with increased happiness and better prices. But players shouldn't be penalized for using the wrong materials, or even just making do with a wood NPC barracks, because some players might not like the building aspect. And that's fine too.
In short, reward players for effort put into making towns, but don't penalize them for enjoying the game a different way. The pylons are enough of an incentive to build scattered, smaller towns. There's no need for that big price increase. And players should be rewarded too for making individualized homes too. Players shouldn't be punished for not wanting to focus on that particular aspect of the game. I hope the devs correct this mistake. But if they don't, a mod certainly will in time, and we can remove Redigit's 'Stop having fun wrong' arbitrary penalty.
P.S. Yes, a 150% price is significant. I have never used money farms, all my money come from exploration and adventuring. It always felt tight before this stupid price increase, and this happiness system is just going to make that worse. It's a good way to make people start making money farms.