Google, Facebook, Amazon, Ebay, Microsoft,, 百度 etc. buy Xeons by the bucketful. They're Intel's customers that matter. The retail box that comes with a fan for sale at NewEgg is just exhaust fumes. 42 or "It's the cloud": take your pick. Managing a gazillion server data center by hand just ain't practical.
Intel's customers that matter replace CPU assets on the IRS's three year depreciation schedule. It's why this  and why ME. Security by obscurity isn't so bad when dumping the vulnerable subsystem lowers overall costs for other reasons [performance boosts and lower power consumption].
ME is a good reason that Microsoft has been striving toward multiplatform. It no longer has such a big say in Intel's roadmap. Yes UEFI and the Windows 10 upgrade process kinda suck, but Microsoft ain't pwn'ing anyone's computer because Intel already pwn'd it. ME going sideways at scale would hurt and Microsoft would be the handy victim.
There's a strategic reason Apple is making it's own chips.