Put simply, technology got better.
Our ability to motion track movement performance is much higher resolution than in the past, we have the storage capacity to actually contain all that data and we have the graphical horsepower to render that and everything else in sufficient quality to make it lifelike,
Its also partly an arms race kind of deal as well. In addition to the technology the budgets for high-profile releases (think Red Dead, Last of Us II primarily) have also skyrocketed, so developers can put more time and resources into body rigs, animation and the systems that transition between all various movements that they do.
EDIT: [This video is a pretty good overview of the animation systems that go into video games](https://www.youtube.com/watch?v=NmLPpcVQFJM). Its framed in a perspective of explaining what might have went wrong with Mass Effect Andromeda’s animations at release, but it does cover a lot of the ground your question is based on.
Latest Answers