Writers take all the aforementioned, churn it about, and release it into content in a voice of their own.
Each writer's content is unique because it flows from their unique brain, unique set of experiences and all the aforementioned. That is, unless they've been caught up in copying others.
Many writers get stuck in a temptation to copy. Then there are times they write from their heads onto a blank piece of paper only to find similar pieces online. Temptation to copy is always present. Feeling as though you've been copied is angering. These, however, are conditions of a writers' calling. Their calling includes risk especially when much of their writing is online for the world to see (or copy). Sometimes the coincidental similarities writers find are merely a product of current trends of the day to which they've been exposed. Many today do talk in a similar voice.
As a writer, don't deny your gift! Don't get caught up in all the would-bes or what-ifs. Use your gift. Use it in multiple ways. Use it in good times and in bad. Use it regardless of pay. Use it because you know it will make someone's life better and your own more joyous and complete.