And Cyrix's fastest processor is a lot less than either.
AMD's prestige, top-of-the-line processor sometimes goes for more than Intel. I think this is supply vs. demand. AMD can't deliver in quantity the highest speed at first. I remember when AMD's K6 233 went for slightly more than Intel's Pentium 233. Usually it has come down within a few months, but lately the pricing has persisted. Maybe AMD is getting some pricing power after all these years with a good product.
Remember, it doesn't cost any more to produce the highest speeds (unless it's a new design or process); they are just able to charge more. Marketing is complex. The idea of a prestige line is to pull up the price of the rest of the line, where the bulk of the sales are. When people see "Intel inside" they think they have a bit of a zoomy P4 even if it is a Celeron. (Make no mistake; Athlon 64s are going to be expensive initially.)
Put it this way: People who must have the best are fools about their money. If you aren't like that, you are going against people like that.
Pricewatch:
Athlon 3000+ $244.
P4 3.0 $396, $152 more