Of the 14 lenses Canon released in the first year of EOS (1987, the 28mm f2.8 was one of them), only 3 are still being made. All the lenses released in 1988 (8 totel, 24mm f/2.8 was one of them) have been discontinued. Here's a list of the oldest lenses Canon still makes (all designs from 20+ years ago):
15mm f/2.8 Fisheye (1987)
50mm f/2.5 Macro (1987)
135mm f/2.8 Soft Focus (1987)
35mm f/2.0 (1990)
50mm f/1.8 II (1990)
TS-E 45mm f/2.8 (1991)
TS-E 90mm f/2.8 (1991)
100mm f/2.0 USM (1991)
20mm f/2.8 USM (1992)
85mm f/1.8 USM (1992)