Personally, I think most people do reach out to others, only to slip back into silence if they don't receive support or receive interventions that make things worse (being involuntarily detained in a ward and things of that ilk.)
Several people I was close to who ctb did reach out to loved ones, health services, friends, etc multiple times, and were met with judgement because their suicidal ideation persisted, or they were placed in wards so many times that they were terrified of being sent back.
It only seems that those who have gone through with the act are silent, because they've often been forced to mask their problems, and because society tends to view chronically suicidal people as "boy who cried wolf" cases rather than believing that a person can feel this way inexorably, outside of the typical temporary vacuum of a crisis which is thrust forward in the public as the dominant narrative.