Just in the last few years: Lagerfeld, Westwood (who was also predeceased by her natural successor Alexander McQueen), Miyake, & more recently Armani. Now Valentino last week:
The remaining big Japanese designers of that era: Rei Kawakubo (Comme des Garçons) & Yohji Yamamoto are both getting up there in age. Ralph Lauren is up there too, and thankfully still active for the brand. With Donatella having stepped down from Versace, who else is left from that period (70/80/90's)? Is Calvin still working?
Mucia Prada, Dolce & Gabbana, Tom Ford (Gucci), Marc Jacobs are a few young-ish [sic] names I know crossing over into this century. I have no idea who is leading classic houses like Chanel, Dior, etc.
On a positive note, I am currently amazed at Coutre to the Max, who appears to be an old soul in this young boy's body, & doing amazing things. Can this be real?