The word was never that FreeSync was impossible, but rather that it was impossible with current hardware. Nothing about that has changed. And it was AMD who said it would require new hardware, so why shouldn't we believe them?
Regardless, this is a good thing. Variable refresh is the future, and I for one don't care how we get it. I do get bothered when companies spread deliberate misinformation that does not stand up to scrutiny solely as a means to rain on the other guy's parade, as AMD did with their original FreeSync demo.
And, just so everyone is clear, updating the DP spec does not change existing hardware. You can't magically get a panel that has zero variable refresh capability to turn into one that does just by adjusting what signals you send over the DP cable. This has all been rather thoroughly investigated already, so let's please not rehash the same debunked arguments once more.
Changes to the DP spec to support variable refresh is a good thing. VESA adopting it is a good thing. But don't for a second think that this step, as important as it is, has any impact whatsoever on hardware. It will require hardware development on the part of display manufacturers, period.