Absolutely agree. There are two ways to launch high-end model for Kia, either to create a new brand or to make a huge revolution internally, so no one associates Kia with Rio or Forte as you said. Of course, launching a new brand is way easier than rebuild the whole Kia company.
The other downside of being in the Kia/Hyuandai/Genesis stable-mate, is that when you go look at a Genesis, and see the exact same buttons and layout in a Genesis as a Kia. Still no respect.
Low cost (normal) cars having the exact same parts in the high end cars really makes the high end cars look unappealing. Cadillac and Lincoln suffer this with Chevy and Ford. I haven't ever looked at Lexus/Toyotas or Infinity/Nissan to see if the same parts used.
Go check out the Genesis G80, no way at all comparison on the exterior, but take a gander at the steering wheel, gauges, door buttons, and center console. What do you think someone spending $60K on a car thinks if they see the exact same design inside a $24K car? The G80 is practically identical to the Optima (interior and function wise)
Agree, it's kinda annoying. Somehow it's connected to the region where a car is produced. Probably Kia and Hyundai have the same third-party parts supplier, which has just a few options for interior details. It seems to be a negative part of the economy in the car manufacturing...