Sad but true: Once you go full voice and performance capture, you have limits... if Larian needed to do that for a Baldur's Gate game? Well, that's a different question. Personally, I wouldn't have minded reading, and reused animations are usually fine if they are subtle enough.
You don't even need performance capture to make it impractical. Look at DOS2, or better yet, Pillars of Eternity which was blatantly going after the Infinity Engine diehards; you
still don't get more than a handful of companions, because even things like writing standards have gone up so much in the last few decades that churning out two dozen companions with one defining character trait just is not an option anymore for AA and AAA production.
Don't get me wrong, I played all those same games in the 90s / 00s and loved them, but that's just not where games are anymore, and there's just not much of a market for it. Personally I think it's all for the better, and would MUCH rather have 4-6 fully developed companions then 20+ who I barely care about and a dozen of which I will never even use. /shrug
