Another thing about text is that it is highly efficient, certainly much more so than voice acting or a cutscene. And it's not only for gameplay or financial reasons; when you limit voice acting and cinematics you can throw whatever amount of lines at the player and they can imbue them with their own imagination, which often makes it much more powerful than it could have otherwise been.
One well-written paragraph can easily and very effectively replace a cutscene, the latter of which typically takes far more time and money to create. When you're on a budget, as in this case, it's a no-brainer.
Chris Avellone has said in the past that he would have preferred in retrospect to have replaced some of the text in PS:T with cinematics, and I've always deeply disagreed with that notion. Text allows you to throw a great number of sensations at the player and evoke responses that you simply can't otherwise, and that isn't even taking into account the gameplay ramifications as far as player choice in dialogue.
Cutscenes are certainly not all bad and they have their place, and heavy voice acting can often add great enjoyment to a game, particularly in the adventure genre. But for titles that are heavy on branching dialogue and/or story paths, going largely with text is probably always going to be a better idea, for myriad reasons.
