I don't think that you can say they are or they aren't.
I also don't think that you can relate wild cat species to domestic cats (excluding ferals).
Our cats are most definitely social (and don't forget - they see their owners as part of their social grouping).
George and Edward (siblings) were particularly close. They used to play together, sleep together - often curled up together, but if not, whoever was the last to go to sleep would go and find the other, and sleep in the same room. They had to be together to be happy.
Now Ed's gone, George is upset - he's getting used to him not being here most of the time - but before he goes to sleep, he still wanders round looking for Edward. He also saw the vet wrap Ed up (his body) after he'd been PTS, and take him out the front door, so he sits near the front door, waiting for him to come back.
Magnus (not related to the others, and introduced about 18 months ago), was solitary at first (he was a stray), but now is definitely social. He meows when he comes home till he knows where everybody is (human or cat). And he frequently used to curl up with one of the others (or both) to sleep. Being that he was closer to Ed than George, he too keeps looking for Edward to curl up with and go to sleep, although he also saw the body.
George has now taken to sleeping in Ed's bed. Or in ours. And although George and Mags don't always sleep together at the moment, they do always have to know where the other is before they go to sleep.
Magnus also has 'friends' outside. A couple of neighbours' cats - I've seen them playing together in our back garden (they're all boys).
Conversely, our bridge boy, Vlad, hated any other cats, and instantly kicked the backside of any that came within five feet of his territory (and dogs as well for that matter...).
In other words, I don't think you can say either way till you know the cat. Domestication means that they're not living in a natural environment anyway (not having to hunt for food, not having to find their own shelter, or generally fend for themselves) - means that other factors come into play. You can't expect them to behave as they would in the wild.
It's really all down to the cat - every cat is different - some will love companionship of another cat - others will be hostile - others will get stressed out and depressed. And yet others will be completely indifferent and show no real response either way.
Since all cats have their own personalities and likes and dislikes, and temperaments, it's a bit daft really to assume they'll all behave / react the same way, or (given the whole situation of domestic cats is completely unnatural) the way that cats in the wild do.