American EMV has some dumb decisions baked in, but as far as speed goes it's not the chips, it's the existing in-store backend processors. A lot of them are over slow and unreliable connections (GPRS is super-common, as are phone lines shared by many points of sale). As processors are forced to upgrade, Americans are seeing faster chip transactions.

Companies that prioritize this--Walgreens comes to mind as an obvious example--have chip auth under ten seconds. It isn't optimal, but it's improving.