Depends on how many is "many". Most graphics programmers on AAA games have 5-10 years of experience and all of them understand the whole pipeline. Games are realtime so you have the natural ceiling of how complex you can get before you run out of time and drop frames. In the VFX you can have people specializing in something like vegetation or fabrics with 20 years of experience just in that and nobody else in the team even approaching their level of expertise.