Leather does that when it ages. It's called character and is what gives leather it's beauty. I don't have leather in my car but I do have a couple of leather couches in my home that I bought 5 years ago and they were flawless at first but overtime they just develop their 'character'. Just keep doing what you're doing with the cleaner and conditioner and it will look good even when the rest of your car sits in the scrapyard someday.