There has been one TOS episode that has been driving me nuts for decades. View the short clip below, and then tell me what you think. I'm of the belief that with 1920's technology there is no bloody way they could tear apart a 21st century cellphone and figure out how to reverse engineer it, let alone figure out how to manufacture the components, and it would be even harder with 23rd century technology. So while it makes a cute ending, and a closeup for Shatner, I give this ending a fail, because both Kirk and Spock would recognize the basic fact of reality.