>>38243707Including all used models needed into scene is very robust. It allows developers to create the scenes without being dependent on a model repository with often changes. It is also easier for the hardware. Earlier games also had different tilesets for different maps, even when some tiles were duplicated.
Remember that Pixar Studios were able to save Toy Story 2, when the main server failed, just because the model files were distributed among the designers.
Fun fact: Red, Green, Blue and yellow contain three instances of the sound engine, just to avoid switching the memory bank too often.