This will mean very little in the long run. Colleges will not see it as a “loss” because they did not know you had the opportunity to become the Editor in Chief. Rather, they will see it as "Wow this kid likes journalism and he did it for all four years. He even showed dedication and took on leadership of being news editor senior year. You’re overthinking this.
Edit: Also I took a look at your other thread, and it looks like you are a rising junior. It is not the end of the world. One girl who was on the yearbook committee joined junior year and jumped from being an editor (the lowest non-staff position) to being Editor in Chief her senior year. I was initially frustrated because she was the section I was a section leader of and I had been a part of it for 4 years, but it turned out for the best. Trust in the process and if you show enough dedication, you can still be EIC. If not, it is not the end of the world.