The last thing anyone with an intel integrated chipset has to worry about is perfect Vsync, while integrated graphics is something that has moved from a joke to something we should take seriously, it's not in the realm of high end graphics and gaming that freesync/gsync is.
What matters most is not so much what 3rd party vendors support it, but what support the 2 major GPU manufacturers have, and with Nvidia dominating market share it almost doesn't matter, most gamers have Nvidia cards. Of AMDs tiny market share a lot of these people are bitcoin miners and GPGPU users who want the faster GPGPU abilities for cheaper and wont be interested in vsync and related tech.