I don't think anybody (especially anyone who looks at the numbers) would argue the Optima is a good value. The point being made here, is that people that are cross shopping the Optima are cross shopping the Camry, Accord, Passat, ETC.
People shopping in the 70k+ market are looking at the 5/6/7 Series, A7/A8/ Merc E/S Class. None of them are aware it exists, and yes, they would be laughed out of the UA neighborhood for buying a 70K Kia, regardless of it's merits or warranty.
Take the VW Phaeton for example. VW Doesn't have the same cache here as it does in Europe. The Phaeton was one the most advanced cars on the planet at the time. The Phaeton was also a 100K VW competing in the same segment. It died a horrible death here, and suffered some of the worst depreciation imaginable. Because, that doctor could never park next to the BMW or Merc in the practice without being laughed out the door for paying 100K for an "oversized vw", despite it being the same chassis as a Bentley Flying Spur.
Brand recognition and "theoretical prestige" are part of the game in that segment, truth hurts.