Highly recommend reading the Jalopnik review of the 2016 Lexus GS F from Robb Holland, a professional race car driver with an eye for the big picture:
All of the assembled journalists in Spain could declare that the GS F is the best performance sedan ever and I could say that it lapped Jarama 5 seconds quicker than a McLaren P1 and sales might skyrocket by a whopping 3 cars.
Buyers in this segment have massive brand loyalty, and I think Lexus knows that they are not going to convert huge numbers of these owners right away. The fact that they only plan to sell 2,000 a year of these in the U.S. is confirmation of that.
Lexus seems to be playing the long game here, and steadily building their reputation in the performance segment is part of that long view. The GS F doesn’t break any new ground but it does move the brand a very solid step closer towards their competition.