Dreamworks used Renderman(Pixar’s Renderman) along with several other commercial package for a Shark Tale. When Dreamworks acquired PDI, who made Shrek under contract for DWA, there was essentially a war between the two pipelines and PDI won. I was on the PDI side of the company, but there was a lot of positive things about the Renderman pipeline.

Because all this animation tech is a moving target, each production's management chooses the software and versions of that software a production will use and then freeze it. So the studios already have in place a subsystem for every production to be running different software for different productions, doing the same jobs as other productions using other software. This allows some experimental renderer to be used in some sequences, and so on, as well as trials of all kinds of software too, such as AI tracking of camera paths, and the soft and hard objects in their view, AI assisted rendering, assisted color timing assistance and then experiments directly with AI video models in a hybrid pipeline.

Both companies each had their own renderer & rendering development team before the acquisition. And their own pipelines. A couple decades later, that’s still true.