"Even more interesting would be a Socket type that stuck around for more than 6 months.."
Just to clear the air... Socket 423 will be more than a year old when replaced. PPGA, almost two years. FCPGA, almost two years. Slot 1, two years.
If you want to compare AMD... Slot A lasted about a year, and Socket A is just over a year old.
So, there's really not much difference between the two. And sure you can say that AMD is going to continue with Socket A. But is it even possible to use a Athlon-1.4ghz with a motherboard purchased 12 months ago? And even if it is, who would even consider it? I don't see that pattern being any different in another 12 months, even if AMD does stay with Socket A compatibility.