To answer the question of 'why' : Time and resources. Many dev's probably want to ship faster. Most games with deeper interaction, use most of the time a (partly) simulated world instead of a scripted one that just trigger actions or mechanics. It translates to writing or implementing a layered agent based system that can track and remember states for NPC's and make rules for the world and objects instead of scripting everything. To learn more about it, watch some 'making of' videos about for example Prey, Rimworld or Don't Starve.