The Neanderthals were the descendents of a population that had left Africa ten to forty thousand years before homo sapiens left Africa. The Neanderthals could not compete with the homo sapiens, nor could the Neanderthals survive as well as the humans could.
The gorillas that exist now do not occupy the same ecological niche as humans, nor did their ancestors (after they diverged from our common ancestor) occupy the niche our ancestor's did.
Every trait that a species carries has a chance of disappearing if it is not useful for successful procreation. Except, some traits are bound up with survival traits, and thus are carried along.
When tails were not needed for survival, they were no longer part of the necessary genes, and thus, due to genetic drift, faded away. Also, they were not bound up with other, more important genes.
Hair for warmth became less important when humans developed brains that could develop tools and knowledge to protect themselves from the cold.
Civilization has been such a tiny, tiny part of human's existence on earth, that we have not, and will not see humans evolving from our current condition.
Life started on earth about 3.8 billion years ago. Let's say that we have a movie that compresses that time span into one year - Viewing the movie would take you exactly one year, starting midnight on January 1st, ending midnight December 31st.
Each second of the film would cover 120 years.
The evolution (starting with the common ancestor of apes and humans) of humans wouldn't even start until December 31, at around 2:00 in the afternoon. For the next nine or ten hours you would watch the divergence of apes and hominids.
Finally, after watching TEN HOURS of evolution, the last 30 seconds - from 11:59:30 until midnight - would be the time that humans were on earth. Hardy much time to evolve.