makes me question how free it is if you have to upgrade gc aswell.
Actually is called Adaptive Sync and is VESA standard for the 1.2a Display Port and onwards. (not the 1.3 though).
It's "street" name is "Freesync" because on contrary to Nvidia Gsync it doesn't require a separate module to work, which costs money and restricted to Nvidia cards only.
However, do not expect old tech to use it. Is like asking why the XXX graphic card or monitor, cannot run HDMI 2.0 or DP 1.2a. Because the hardware simply wasn't designed to support them.
Also because is a under VESA Standard, Nvidia can support it also (anyone can even Intel), however it seems they opt out to ignore it and keep milking their customers.
Because if someone buys a GSync monitor, and want to use variable refresh rate, is forced to use Nvidia graphic card until the monitor is replaced.
ofc you can use the monitor with another card but it will not support it
Closing, if Intel gets it working with the next gen of IGPs going to be fun, because here we going to have pretty low powered graphic modules, been able to play games even at 30fps and not feel like a slideshow (ok quality wise going to be pants though).