While it may not be required anymore, one node per process still looks to me like the default paradigm in ROS2. If people are actually eschewing that approach, one would expect the ROS to update their docs to reflect these new best practices. Yet, their beginner tutorial and robot example still use that as the model as do many of the open source projects I have seen. I can't comment on how industry practices have evolved around ROS2, since my job still uses ROS1.