Why is IEeeeeeeee! still around? Does anybody know?

When the news came in that in Windows 10 Microsoft will be releasing a new browser codename "Spartan". I had the same thought, why new browser? Why not just make a UI that will let me download other Browser like Chrome, Firefox and Opera.

I had to download chrome via the inbuilt ftp once because IE wasn't working and the pc had no working usb ports nor other forms of data transfer ports and no other pc in the network to download via smb from
Still faster than IE