Sierra's AGI and SCI and Lucasfilm/LucasArts' SCUMM were strokes of genius and have been a major factor in these companies' success. It allowed them to not just churn out games at a far greater pace than if every game's tech had to be built from the ground up, but also made porting to other platforms much easier. In that sense they are the predecessors of Unity and Godot and all the other game engines we have today.