Performance is not the issue. Contrary to desperate SV hunter belief, bad performance is easily fixed so the success and failure of a spec can't be judged by how well it performs (e.g. can Blizzard just blanket buff a spec by 30-50% on all abilities then call it "successful"?).
Parse count is the issue. That indicates how many people are playing the spec. Survival is making other unpopular specs (e.g. Subtlety Rogue, Feral Druid) look positively thriving. The picture I posted was the default from the page you posted, just sorted by parse count.
Now, some SV hunters love playing a niche, "not-for-everyone" spec and I've seen the whole "there's nothing wrong with a spec being unpopular" angle. That may be true. However when you are talking about a spec that was once upon a time extremely popular (routinely one of the most popular DPS specs in the game, in fact) that now is stuck in a position of massive unpopularity (SV has been fluctuating between 20-30% of the parse count of the 2nd-least-played spec for the whole expansion despite numerous buffs), it's hard to look at that and not conclude that something went terribly, terribly wrong.
But it's performance is the issue. The thread is a person asking about maining SV, and you're talking about popularity. You also showed Mythic only, where heroic and normal have many more people playing it. Granted, the numbers are low, but it's been discussed to death why this is, and the spec being good or bad as damage numbers and playstyle have never been mentioned. Not once. You haven't been able to retort that they do good damage and are viable and are focusing on popularity.
Now granted, I know that some of your replies are to people discussing popularity, but again, it's not what this thread is about. Much like the other thread talking about success and failure.