Apple does it more sparingly (now), and fairly consistently: as a product line evolved. The iMac line did it when it was "cool", the iPod was the next one, and the iPhone evolved from the iPod so it made a lot of sense (and thus so did iOS). There's not really anything else Apple names this way. Apple TV, Macbook, Airpods, Safari... Whereas with KDE everything has got to have a K, it's pretty ridiculous. It's also not a particularly "pretty" letter and you end up with names that are either purposeful misspellings, midKapitalized, are plain bad puns, or occasionally and at best, are merely oKay.
KDE does not have a great brand. Apple does.