In the non-IT world, systems engineering is about building solutions using components, sub-assemblies, assemblies of sub-assemblies all the way to the complete solution.
Such systems are deigned by starting with a top-level goal/problem and the decomposing the solution through a series of layers. The construction then takes place from the most granular low-level components.
In the naive interpretation of the word "generalist" you would be conflating a chemical engineer with an aeronautical engineer. But when you are build a petroleum refining plant you want chemical engineers to be dictating the top level design whilst for a wind-farm you would want aeronautical and electrical engineers doing the top-level design.
Software engineering mostly deals with intangible "objects" so the rigid distinctions are rarely enforced. Unlimited degrees of freedom leads to many amazing possibilities and also the biggest disasters.
