I would be surprised by that.
The whole tech sector has been down for a while - mainly because it's been flooded with lifeless products that aren't noticeably better than the lifeless products that came before.

There just isn't a lot of reason for most people with a Pentium III-ish computer to upgrade.
It's true that AMD isn't competing as well with Intel as they have in the recent past, but I believe this is cyclical. Both companies have their place - I believe that the Pentium III chip is the best all-around for recording, for instance, while I wouldn't hesitate to tell a hardcore gamer to get an Athlon. If enough software is written to take advantage of the Pentium 4's unique (strange?) design, then it may find itself at the top of the heap.
The PIII is still my favorite all-around CPU, though. It's a great design.
IMO, AMD isn't showing any of the telltale signs of severe trouble. They're expanding, not contracting (see: the upcoming "Hammer" chips). Remember when 3dfx went under? First the Voodoo4 and Voodoo5 were delayed. Again, and again, and again. When they came out, they weren't competitive against the GeForce2. Then the Voodoo5 5500, the card that everyone thought might compete, was delayed even further. I remember hearing about an even more powerful Voodoo5 6000, but the card never was released to the public. I believe some reference boards exist, but I don't know if anybody was even allowed to benchmark them. Then it was, "We're getting out of the retail card business. We're going to license our chipsets to other manufacurers." A few weeks later, it was "Uh, no, actually we're going out of business."
AMD isn't doing any of that. I really don't see any cause for worry.
The words of an outsider, yes - but an outsider who's been looking in for many years.