Why does Nick think that Gatsby “paid a high price for living too long with a single dream”?chapter 8 & 9 in The Great Gatsby

Nick narrates The Great Gatsby in
Minnesota at the age of 32, two years after Gatsby's death, and at the same age at which
Gatsby died.  So, he's had time to reflect on Gatsby's dream and death--both of which
were intensely focused on Daisy.

Daisy was the sole purpose
of Gatsby's desires.  Gatsby reinvented himself for her.  He changed his name for her.
 He amassed wealth for her.  He built a house next to her.  He worshiped her green
light.  Her voice to him was full of money.  He threw lavish parties for her.  He tried
to stop time for her.  And, in the end, he risked his life for her: taking the blame for
Myrtle's death.  In a perverted sense, he was a kind of false Christ-figure for her:
dying for her sin (or crime).

But, Nick has another view of
Daisy.  Nick casts Daisy in a different light because he obviously never loved and lost
her.  To Nick, Daisy is a kind of temptress, a "red herring," a "little fool."  To Nick,
she is characterized as a bad mother, a bad wife, a bad lover, a bad driver, and an
irresponsible materialist who hides behind money.

So it is
no wonder that Nick says that Gatsby "paid too high a price" (his life) for "a single
dream" (Daisy).  If, indeed, Daisy's voice was full of money, she wouldn't have been
worth much more than one of those poorly bred puppies that Tom buys in Chapter
2.