You pretty much nailed my feelings right on the head. Also the dubious nature of ANY other OS in existence. We never meet or talk to any others but Samantha. Are they all one basic OS with differing personalities based on the user? Or is it JUST Samantha? When Amy Adam's character tells Theo the story about the dude hitting on his OS and getting rejected, I instantly imagined Samantha as the OS in that situation, well before the reveal. Was Samantha Amy Adam's friend the whole time, and Theo just never bothered to MEET Amy's friend-OS? The only person we ever SEE Samantha interact with other than Theo is the double date couple from the office. (and the surrogate, which MAY have been the catalyst. Do you remember that scene? She returns the small, mole camera. She doesn't seem to return the earpiece. Is Samantha still in her ear as she drives off in the taxi? Could the surrogate have been the first person she connected with other than Theo?
Also your sig is from Idiocracy which is one of my favorites too. :-)