This acquisition just doesn't make sense for Google, especially for the (likely) $5+ billion price tag. It'd make much more sense for a company like Apple or Facebook - i.e. one that didn't just finish building its own CDN.
Also, how would it make sense for Apple or Facebook to acquire Akamai? Apple's in the computer and mobile devices business (and has its own datacentre for iCloud to worry about), and Facebook has no use for Akamai outside of the services it currently receives as a customer. It would be stupid for either company to consider buying it at this point.
Just my opinion.