Not a fair comparison. The private servers were written with the small hosting in mind. They would very likely never scale to what Blizzard has in place. For all I know, Blizzard could run their stuff on a Mainframe with specific platform optimizations against an IBM DB2.
But I also don’t think this has to be transferable to a local setup without effort either. Once they release the source, people can refactor or reengineer it to run on smaller scale, replace proprietary databases with free ones, etc.