Build you own computer, ignore Windows 8

I wouldn't waste my time and money upgrading old xp computers to Windows 7 or 8 since they are probably older and slower cpu's and small memory sizes.
However I always tell people, if your present computer is doing what you want it to do then why upgrade or buy a new one.
You can't buy a new one now that's loaded with anything but Windows 8 so the only way to get Windows 7 on one probably will be to buy Windows 7 CD's and install it back over the Windows 8.
I've tried Windows 8 and I don't like it. I use a backup program called Acronis True Backup so I reloaded an image of Windows 7 in about 5 minutes and threw the Windows 8 CD's up in my cabinet to collect dust.
I don't why all the forums have ways to make Windows 8 look like Windows 7, why?