what a cool piece :d/
From my experience, I've found that pinks are almost always the first color to fade. I think some of the most sturdy pinks I've seen are those used in Karabagh rugs around the first quarter of the 20th, but even these show weakness.
Pinks literally seem to "evaporate" just as seen in pics you posted. I wonder why this is, I mean, there are plenty of other light colors that one would suppose might vanish similarly - you would think with chemical dyes this could get cleared up, but it's not unusual.
Great pix by the way, how did you come about it? it does look like it could be around 30-40 years old, I'm just not too familiar with these types to say. Really cool changes in weft color. This reminds me a little of my favorite types of rugs right now: polychrome warp sennehs. They sometimes call them "rainbow" sennehs, most of which are now around 100 years old.