Value of cryptocurrencies: Why does noone make Bitcoin2, 3, 4,...?
Why does noone use the exact same technology of the Bitcoin and create Bitcoin 2? 


They have, there are hundreds of copies of bitcoin known as "altcoins", one prime example is bcash.


  If they did, why would a Bitcoin2 be worth less than a Bitcoin? 


Because there is no demand for a bitcoin2. No one wants one because its not a real bitcoin. The only value bitcoin has is in the demand people have for it - how much someone is willing to pay for it.