Perhaps so many of these have been returned for AF problems that retailers are complaining loud enough to Canon. Would be the only reason I can think of for a shortened life cycle.
Cams: Canon 5D3, EOS M
Zooms: 16-35mm f/4L IS, 24-70mm f/2.8L II, 70-200mm f/2.8L IS II; Primes: 22mm f/2, 40mm f/2.8, 50mm f/1.2L, 100mm f/2.8L IS, 135mm f/2L, 600mm f/4L IS II
Support: Gitzo GT4542LS/G2258, RRS BH-55, Wimberley WH-200