why 21mill coins is the same questions as why there are only 171,000 tonnes of gold on the planet. as that equates to less then once ounce of gold per person for the whole planet...world wide wealth exceeds the amount of gold in the world.
what about all the bitcoins lost? is the same question as what about all the gold in computer parts that ends up in landfill.. or tainted by being mixed with other metals to make it impure.. well the answer is that people have to share a depleting rare 'item'