It shows, Blender has come a long way, but FLOW doesn't look technically incredible. On the otherhand, I just rewatched Shrek recently, and complex graphics isn't everything.
Blender comes with two renderers: Cycles for production rendering, and Eevee for near-real time preview. This movie was rendered with the latter. Like any 3D package, you can also install other renderers. So any perceived deficit in picture quality here is more to do with budget than some limitation of Blender.
Yeah, the real time stuff is pretty solid in blender but for very high image quality / realistic prerendering, blender is still missing a lot of the professional/proprietaries tools that gives the last 10% of polish in big budget productions (photorealism). The community has done a great job in last 10 years but there's still a lot of technical tools locked behind something like max/maya ecosystems professional paywall that most people eventually transitions to for "serious" industry work because pipelines are hard to change. At least that's the state a few years ago.