Both BG1 and BG2 combined were made on a budget that these days wouldn't net you the cinematic intro for BG3 and its tutorial on the ship. BG2 in 2000 had a budget of... what? Less than 5 millions or so?
And what was the budget for Icewind Dale? Which had character-based choices in dialogues. So why would character reactivity be such a big financial hurdle for BG1&2? You even have an example of a stat-based dialogue in BG2: the wish spell.
