I understand your argument very well about desktops but my main questions is about Intel's manufacturing and marketing capacity to fight the desktop space on price, thereby squeezing margins even further. AMD would be gaining more and more of less and less.
We haven't talked die size in a while, but there are several interesting things with die size. In the desktop space, AMD has a much smaller core and then uses a smaller cache on top of it to have a much smaller die size for the same or better performance. Intel has much better cache density, which partially makes up for their need for larger caches. Intel 300nm wafers also partially makes up for their die size disadvantage. Overall, AMD has the advantage here until Intel goes to 65nm. So from now till 1Q06 or so, AMD should be able to gain share pretty quickly unless world demand grows too fast. In the case demand is very strong, AMD should just cut down on cache size and make more chips (since competition isn't strong in a high demand environment).
When Intel is at 65nm and AMD is at 90nm, Intel has the advantage (if they have decent yields), but when AMD gets to 65nm, they get double advantages (65nm and 300nm) at the same time, so it is back to AMD's smaller cores and less need for cache. About this time (late 2006), Intel comes out with their new core and it looks like it is small like AMD's, but possibly more powerful (4 instructions at a time vs. 3) but still missing the integrated memory controller and scalability of hypertransport. Clearly AMD needs to update their core sometime in 2007 and not just go to dual core, quad core, 8 core, etc. We have seen nothing public on this. If they indicate no new core at the November Analyst day, I will start to worry.