Let's see.. there hasn't been a new PowerPC desktop chip in six years, but you really think the x86 is ending its life. Despite the fact Intel and AMD sell over half a billion CPUs a year? Despite the fact that Intel is nearly 15% of the IC industry's sales, but nearly half of the profits for the ENTIRE chip industry (hint: the AVERAGE CPU is sold for $6.00.... ?
I would argue that, technically, x86 is dead. It exists in RISC emulation layers and x64 is steadily erasing its footprint.
And thankfully at that. Intel has been flogging that damnedable 32-bit stuff since 1983, meanwhile 64-bit chips have been floating about since around 1990. It is about time that 64-bit made a strong landing on the desktop.
And as much as people hate Microsoft, it has done something right with Windows 7: in order to obtain WHQL status for a device, a manufacturer must provide 64-bit as well as 32-bit drivers.