There isn't anything wrong with your implementation/configuration, this is standard. Even though the 'Event Enabled' box is checked for the Company object, it isn't process-enabled in the system - not all objects are and there isn't a reason beyond it was just not designed to do so.
It seems the need/desire for this has been on the low side. I did find an old enhancement request asking for this capability to be added, but it was not implemented and has not been raised yet as an Idea on these communities by any other customers before you. You could create the Idea so it can be considered, but there are not any short term solutions available sorry.