Boot camp 6.0

why is not possible to all mac user to have the update of the boot camp?

Trying to download the necessary windows support files most of the times the delay is tragic more than 9 hrs and sometimes is not possible to be written the downloaded file on my usb.I tried to download from apple's support site but when i run it on win 10 the message that this bootcamp ver is not for this pc shows.

Any idea how to install win 10 and to receive also the drivers?

OSX 10.10.5 ON MACBOOK RETINA 2015