Even if it's a socket, Intel's been churning out new sockets every 2 years or so. On desktops it's gone LGA 1156 (2009), LGA 1155 (2011), LGA 1150 (2013). For servers it's LGA 771 (2006), LGA 1366 (2008), and LGA 1567 (2010). You have a pretty limited upgrade window. One tick/tock, and then your socket is outdated.
The new Mac Pro, provided it's socketed, would be on LGA 2011.