I learnt something unique from this post and i would like to add some ideas of mine.
Firstly, I would love say Motivation doesn't set in without having a dream that keeps you moving. A dream that ask for more always brings motivation if you truly want to fulfill them
You mentioned about a short/long term motivation.
It is nothing to see your motivation expire but i believe it does that when you ain't sure of the path you are walking on to success.
To have a long term motivation, it has to do with you. To have a long term motivation, you must have a clear vision of you destination when dreaming