Many things in life aren't fair. People shouldn't be judged by how they look but it's an undeniable fact that grooming and appearance can make all the difference when it comes making a good first impression.
The same applies when it comes to writing. A person who writes well has a much better chance of getting ahead in life and I've experienced this first hand in my own career advancement.
My first job was with an American multinational and I was promoted within 6 months of joining the company.
I wasn't promoted by my immediate boss. He was a typical insecure sinkie who considered me a threat and treated me badly. I was promoted because instructions came from head office 7000km away that I deserved a promotion. The people who issued these instructions had never met me. They initiated the process because they were extremely impressed by the written engineering reports that I was providing on a weekly basis regarding a product transfer.
My English is average at best. However, I was up against very weak opposition as most Engineering graduates at the time were very talented engineers but they didn't have a clue when it came to presenting their excellent work in the written form. I guess they also felt that as long as they were top notch engineers and experts in their own fields, the ability to present their work in writing was secondary as I never saw any of them making attempts to improve their English. As a result, a half baked engineer newbie like myself was promoted ahead of those who had been there for years.
I truly believe to this very day that if it had not been for the effort I put in to learn English grammar, I'd still be languishing in sinkieland in some dead end job.