[helldritch]

At least in terms of movies, this seems like the obvious route:

It used to be that game engines had real-time processing requirements (60/30/15 frames per second) and were constrained by the hardware on which they ran, but movies looked more photo-realistic and could take hours or days to produce a single frame.

As silicon and algorithms get faster and closer at approximating reality, the difference between the output of the two softwares approach one another. Given the amount of effort required to build these softwares it makes sense to save the years of effort, cost involved and risk involved with what essentially amounts to building a bespoke, internal graphics / physics / particle simulation engine.