You are absolutely correct, you will have "low level" people in charge at one point or an other. The difference is they will be the initial IC, if the incident is big enough or escalates command will be passed to a more experienced commander. The initial IC can easily handle managing his own crew and maybe a couple others, but he would be overwhelmed by workload and span-of-control quickly, so that initial IC passes command to a more qualified commander. If the incident is big enough, the command structure can be expanded. In the public safety world, that means populating positions in that structure with experienced people. From my point of view (as an Engine Captain and a Safety Officer trainee on a Type III all hazards IMT) this is how the command structure should be filled... In my experience this is NOT how the positions are filled in many IMTs since NIMS has been implemented.