It's not just learning how to use a new one. There's doing the research to figure out what you should buy. I've helped tech-illiterate friends shop for computers before and it's easy to see why they'd find researching the purchase of a new device frustrating. Most of those friends were easy prey for salesmen who tried to up-sell them. A few friends were setting themselves up for a bad purchase by placing form before function. Either way, they ended up feeling ripped off when they had to shop on their own because they felt as though they paid way too much or got way too little. (Incidentally, they were very smart people. It's just that their smarts were elsewhere.)

So yeah, I can see why people would want to get the same model again.