Appengine's whack pricing says: we'd like to kick you off appengine onto GCE but that would scare away all the enterprise users from GCE. If we announce regular Moore's Law following price cuts for GCE and nothing for appengine, well hey, we can't stop you leaving. We're totally not twisting you're arm! (aside: we are)
"A commitment to Moore's Law: https://cloud.google.com/pricing/philosophy/ "