You're not looking at the "indie scene" part of that. Consider what you thought the future of Terraria was going to be, based on what Re-Logic had said, versus where we're at now. Re-Logic basically went from treating their game like an indie title, to treating it like a AAA title.
Given what they'd said in the past, yeah, I think promise of the game crashed and burned. What I thought would be a game developing over several years turned into a game developing and finishing in under a year. When I look at how much love was poured out on the game by its fans (I think it generated as much as art as DF does)...yeah. Of all the things I expected Re-Logic to do with their success...selling the guts of Terraria off to the art guy to start his own game, packing up and leaving was not among them. I do remember when they started talking about their ethos, they said they made the game because they wanted "their own game." Now it seems like it was less about the game and the ideas behind it, and more about trying to have a commercial success.
Or to put it in other terms, I expected out of Terraria something approaching DF's level of commitment to their own game. And why not? Sitting on millions, it's not like anyone expected anything else out of them than what they were already doing.
I suppose if your metric of success for indie games is that they catch the popular imagination, sell millions and then close shop, yeah, Terraria has nothing to complain about. Games that continue to grow and stay supported by their fan bases is what I consider success for indie games, and in that sense, Terraria be dead.