hype abandon

When someone gets hyped up for something, only to ditch it when that something actually comes out.

Person A: OMG, I'm so excited for Super Platformer 9!
*Three weeks later...*
Person B: Hey, Super Platformer 9 came out today!
Person A: I'm not interested.
Person B: Really? You've been telling us about it over the past few weeks, only to do a hype abandon the day it releases?