I thought players could only sign deals up to 5 years with their existing team and 4 year contracts with a new team (in reference to the statement that KD could have signed a 6-7 year deal).
As far as KD's status, plenty of people have reported that pretty much any team that was in on him prior to the injury is still in on him now, even if he is projected to miss the entire first year of the deal. Plenty of teams are said to be wiling to offer him a max contract. So I don't see where Durant "remains unsigned" in the first paragraph of this post. Technically, he can opt in and stay in GS for another year at $31.5M if he wanted.
So Durant could still most likely pick from: a 4 year, $164 million from another team, stay in GS for 1 year and $31.5 million, or potentially re-sign a super max deal with the Warriors for 5 years and $220 million. The average return time for an Achilles injury has been reported at 9 months (with more extreme cases taking a year).
It doesn't seem like great business sense to pay him $30+ million not to play next year, but it doesn't seem like teams are thinking that way.