Your first sentence explains why the rest of your message is misguided.
To you, building a centralized base is important. To you, that specific method of gameplay and advancement is the most enjoyable or "correct."
But that's not what I said. Indeed, I never even claimed it was particularly "enjoyable", let alone correct.
My point is that the game is
designed around it. Significant aspects of the game are built under the assumption that you will have frequent trips back to base. That's not about what's important to me; that's about what's important to the game.
Terraria is not a magical "do anything" box. There are limits as to what you can do, and the game is designed to condition certain behaviors into players, rewarding some behaviors and punishing others. You cannot enter Hardmode without killing the Wall of Flesh. You cannot fight Plantera without first killing the three Mechanical bosses. You cannot fight the Moon Lord without first defeating the four pillars. And so forth.
And you cannot collect more stuff than your inventory will hold without having a place to dump the excess off. And the game is designed with the expectation that you will have such a place.
Removing that limitation is akin to removing the mana cost of magical weapons: it's conceptually simple, but so much of the balancing and design of the game is built on assuming that magical weapons cost mana that if you did so, you're now talking about a completely unbalanced play experience.
And hey, maybe that would be a more fun play experience. But it's not
the same experience as Terraria's play experience.
Even a cursory browse of these forums will demonstrate the varied approach users take with this game.
There's something important to remember:
Terraria still has to work for people who've never played it before.
That's something that people who've played this game for years often forget: what it's like to start fresh with absolutely no idea what's going on. What it's like to try to learn the game without going to the Wiki or without using other outside knowledge.
These are the people who, with infinite inventory, are going to spend all their time underground, and then have no idea how to progress. These are the people who will forget that the Guide exists and not learn important tasks like building houses and such. These are the people that I was specifically talking about.
Terraria is different from and superior to Minecraft because it has a clear progression system and it is designed to try to push you along that system. And part of that process involves going back to the surface regularly.
Take that away, and the experience becomes something quite different.