Yes, engineers MUST communicate well to succeed
My career accomplishments are not so sparkling, but I've made a decent living for years as an engineer who could write and present to audiences.
In my large American high school, I was denied participation in the first-ever advanced placement course in English, despite straight A's previously. The single guidance counselor for 1300 students advised me to seek a technical education because I had straight A's in math and science. I was worthy and financially deserving of a scholarship for full tuition and books at Case Institute of Technology, a forerunner of Case Western Reserve. I did passably well in courses there, including two programming courses and four semesters each of Calculus/Differential Equations, Chemistry and Physics, including lab work. But my liberal arts leanings made Case and uncomfortable fit. I gave up the scholarship, began working as a programmer, transferred to Western Reserve next door, losing credit only for a course in which I attained a "D", a barely passing grade. I completed my studies with a BA in English Literature, taking graduate level courses in linguistics, old English and non-Shakespearean middle English literature. I graduated at the end of the summer rather than the spring of my senior year.
So I have been an English lit major masquerading as an engineer for decades, working variously as a software developer, customer-facing support person, project leader, manager, presenter to a couple of thousand tech people, negotiator and self-employed personal computer fixit guy. It has worked out well for me, enabling me to live in different areas and climates including one year in the old Yugoslavia, one year in Belgium and four years in Italy, fulfilling my dream of living outside the monolithic and provincial United States. Financially, it has been good, but I am not exceptionally wealthy.
Being able to communcate clearly and succinctly is most important, in engineering and in ANY career.