As the inventor on twenty-something patents, I think you're understating how much input engineers have. Yes, the bulk of the work is done by patent attorneys, mostly translating from pure technical jargon into that weird mixture of jargon and legalese that patents are written in ("...of the one or several..." and "...such as but not limited to..." and all that rot). However, for a patent of any complexity this often involves multiple rounds of back-and-forth with engineers to clarify and ensure correctness. In fact, I'd argue that any engineer who isn't involved in the writing process is failing to be sufficiently diligent or act in good faith when they sign the part about the patent accurately reflecting the invention.