The devices people referred to as "mobile" for all those years weren't ever really intended as PC replacements... except perhaps in the developing world, where there weren't many PCs to replace.

"The post PC era" is meant to refer to a world where (except in some specific professional contexts) people largely stop buying PCs because of a new class of mobile devices that takes over their workload entirely.

If I say "the mobile era" to people, that means something very different than "the post PC era". This is what language is for. We create new words so we can talk about new things, even when they're small changes.

Larry Ellison whines about the word "cloud" and insists it's just "servers". But "cloud" is about instantaneous provisioning and other infrastructure that lets you target an undifferentiated set of servers, rather than having to administer each server one by one. And unlike a "cluster" you don't generally own the whole thing. What word should we use, if not "cloud"?

Yes, it's still servers. Yes, the iPad is a mobile device. Yes servers and mobile devices are old. But whats your problem with using new words for the parts of these phenomena which are new?