Re: Those GUIs ARE only frontends!
2000: Nope, never. XP "by accident" and not planned and with unloved side effects when it kicked in. Vista was the first, albeit without much effect. Improved with Windows 7. And the big step was with Windows 8, causing more issues regarding this than before. I had to tell the users "wait for the network icon in the lower right corner before logging in".
8 an 11 are alike: Below the hood are some really good improvements, but the UI f*cked up. Windows 8 was the first which made consistent 113 MByte/s over gigabit LAN possible with its TCP/IP and SMB optimizations with cheap network chips in consumer PCs. At the same time needing less CPU power to do the same copy job on the same hardware.