Consider the example graphic above. Most of us wouldn’t have a problem hearing these words in spoken English. However, written English is a different animal.
Instead of is grammatically incorrect when using the preposition from to create a hierarchical construct. Why? Because instead of by definition implies that someone is choosing between two options. But hierarchical structures aren’t about options; they’re about order. They proclaim an arrangement between a set of elements.
That’s why rather than is the grammatically correct form. By using from to establish a hierarchy between two elements, the writer says that Element 1 belongs in this place and Element 2 belongs in that place. Rather than says, “This is the order, not the other way around.” It brooks no room for discussion. Instead of implies that the order could be the other way around if someone chose it to be so. Often when using from in a hierarchical structure, that simply isn’t the case.
The graphic above provides a great example. Welds don’t crack according to the will of people. Unless the weld is designed to fail in a particular fashion (and most welds aren’t), we don’t get to choose how cracks nucleate or propagate. The writer of an investigative report isn’t presenting options from which to choose so much as explaining why one idea matches observed evidence and another idea does not. In essence, the writer is communicating a hierarchy between two different ideas (this one is right and that one is wrong). Thus, rather than is the appropriate expression, not instead of.