If the range were that old, we’d observe massive erosion, considering the extreme weathering they endure, from rounded festures to smooth surfaces. “50 myo”, lol.The Himalayas are one of the world's youngest mountain ranges, at about fifty million years old. Mountains form where two continental plates collide. Since both plates have a similar thickness and weight, neither one will sink under the other. Instead, they crumple and fold until the rocks are forced up to form a mountain range. As the plates continue to collide, mountains will get taller and taller.
But what do we see? Crisp & well-defined characteristics, denoting a very youthful range, geologically speaking. Regarding most of the Earth’s high ranges, from the Rockies to the Andes, we observe youthful features....but granted, the rocks from which those features derive, are old.