This is according to my text :


[![enter image description here][1]][1]


Well I understand why more of Elimination reactions happen at high temperature,but why do Substitution reactions have their yields decreased as temperature goes up?

This is according to [master of organic chemistry; (Even though it says that there is a relative increase, the graph shows a $decrease$ in yield of the substituted products)](website) :
[![enter image description here][2]][2]

Aren't they supposed to have their output increased as well,as the activation energy barrier has already passed and rate increases with increase in temperature, Or am I missing something fundamental here? 

Also, what could happen just after the energy barrier is broken for any one of the reactions?


  [1]: https://i.sstatic.net/3xTjL.png
  [2]: https://i.sstatic.net/c9Dl9.png