To become a chemical engineer, you first have to complete the course work for a degree in chemistry. Chemistry as chemistry is an extremely modular subject matter; you can solve most problems in discrete steps in isolation. In a computer science sense, chemistry is about pure functions. Very easy to analyze, as material side effects (like spontaneous detonation) are rare.
Chemical engineering, on the other hand, is about analyzing systems that leak their state everywhere and have effects that feedback into other parts of the system. But it needs to be extremely efficient nonetheless. There is no isolation because it doesn't exist in real-world complex systems. I have seen excellent chemists absolutely fail to grok chemical engineering even though it is literally the same subject matter. The only difference is that chemical engineers are required to reason about complex distributed systems; as with computer science, only a minority of practitioners ever seem to grok it despite their best efforts. Same problem, different domain. And chemical engineers are paid on a different scale than chemists as a result.
In engineering, bimodal distributions are the sorting of people that naturally have the ability to easily reason about complex distributed systems with many concurrent moving parts and people that cannot. Increasingly, the market is discriminating on this characteristic and it is reflected in wages.
Anecdotally, it is somewhat well-known that people competent at chemical engineering find advanced software engineering to be intuitive; it is a very easy second "language" to pick up. An inordinate number of chemical engineers end up in high paying software engineering careers -- it comes very naturally and lends itself to the abstract analytical toolset you develop as a chemical engineer.