You're missing the edge, which is very very broad.
Suppose your employer wants your web app to interface with an industrial PLC, or fetch data from a car's CAN bus, or talk to a vending machine (ironically the sort of machine that Java was originally designed for).
Most bootcamps don't teach enough fundamentals for someone to figure out how to write both client- and server-side code for those sorts of situations.
Or on the other end of the spectrum, could you write hypervisor code to manage the sort of mass-scale VM deployments behind most cloud providers? It would be very difficult to be an expert on the "full stack", if you think about it.
So...tl;dr, most of the application layer? Probably the physical layer too, any how many of us really work with the link layer?
Suppose your employer wants your web app to interface with an industrial PLC, or fetch data from a car's CAN bus, or talk to a vending machine (ironically the sort of machine that Java was originally designed for).
Most bootcamps don't teach enough fundamentals for someone to figure out how to write both client- and server-side code for those sorts of situations.
Or on the other end of the spectrum, could you write hypervisor code to manage the sort of mass-scale VM deployments behind most cloud providers? It would be very difficult to be an expert on the "full stack", if you think about it.
So...tl;dr, most of the application layer? Probably the physical layer too, any how many of us really work with the link layer?