The best "fix" for a leather dash failure, is prevention. While it could be a bad glue, or sewing, or installation when new, it is important to do what one can to reduce UV and heat impact on the interiors of our cars. My son has a friend who has had the dash replaced three times on his daily driven Aston Martin. The dealer has told the owner that they will not replace it again, it. is up to him to protect his dash more than he has thus far done. Leather dash's are a real upgrade to a car's interior ambiance. But that choice comes with the obligation to reduce as much as possible the inevitable problems all leather will eventually have. My QV has the UV reducing windshield, and I have more protection for my glass and interior with an expensive film on the windshield. But I still park it in my garage (I know not every one can do the same) and if parking for more than a few minutes in the SC sun, I slip my reflective sun shields on.
I have no idea what Alfa claims about leather deterioration, and the OP's certainly is pretty bad. But perhaps it would be appropriate at the first sign of any leather problem to bring it to their warranty attention. By the way, when I see new cars parked on a dealer's lot in the sun, for months at at time, I just cringe at the searing heat and rays on their dash and interior. If the OIP's car is out of warranty, there isn't much he can do. Some years ago, my son had an engine failure in his Porsche, out of warranty, and they provided a new engine, and he just had to pay a small amount for the removal and install. And two years ago, had a valve train problem in his Toyota suv, and again out of warranty, Toyota paid for the repair. One can only hope....
I agree having a good relationship with one's dealer and service department may help in some cases. Not long ago, I wanted new trunk pneumatic struts replaced, they were just a little saggy, and my service rep, with whom I get along great with, told me "..sure, I'll put new ones one". My Alfa is still on an extended warranty, and struts were not expensive, but there was no push back for slightly droopy struts in what passes for winter in SC.
The OP's dash looks awful. I have my own horror story. Few years ago, a respected Porsche racing shop damaged my GT3's engine, and they refused to cover the over $7K it ultimately cost me to get it made right. I hope the OP can have his problem resolved somehow. NV