Relatively speaking, it is frequently changing. I can plug a depression-era radio into an electrical outlet and it will work. Delivering power via a cable, even with AC/DC conversion in the middle, is a solved problem. I can think of five Apple devices currently in use in my house that can't share the same cable. None of them are more than seven years old. That's nonsensical. The fact that none of them can use the same connector as other non-Apple devices merely adds to the annoyance.

As for MagSafe, it's only a partial success. All of my MacBooks have outlasted their original MagSafe power supplies. They aren't robust, can't be easily repaired, and are expensive to replace. I'm happy they're easy to use and help to prevent damage to the laptop, but Apple should have fixed the other problems by now.