Children who are "a bit" gifted are less out of sync, and therefore struggle less. But I do think that if you're a 5 year old with the intellectual ability of say, an 8/9 year old, it's fair to say that friendship issues probably are pretty much inevitable.
No, no, no! And no again! Friendship issues are not inevitable for those children, and this kind of thinking makes me really mad because it ruined my childhood. I did have social difficulties as a "gifted" child but it would have been so much better for me if someone had actually addressed this and invested in helping me to interact more effectively with my peers instead of just assuming that my struggles were inevitable because I was "gifted".
My dd is every bit as "gifted" as I was, probably more so. Academically, she has consistently been working at a level far above her peers. However, she is lucky enough to be socially "gifted" as well. She can make friends with anyone. She has always loved talking to adults and spending time with older kids, but she also loves being with her peers and with younger children too. Yes, there may have been differences in cognitive development between dd and her peers, but that wasn't necessarily a bar to forming friendships - any more than an age gap of a few years is a bar to siblings playing together happily. Yes, the dynamics of dd's relationships are not always perfectly balanced - I can see that she is looked to as the "leader" in her group of friends - but her friends adore her and she adores them. And while her friends might be in awe of her academic abilities, she sees lots of other positive qualities in them which she truly values. Life is about so much more than being smart. She is happy, and that counts for a lot.
I found social interaction much, much harder as a child. I was painfully shy and it was much easier to stay in my comfort zone of having my head stuck in a book or only interacting with another child who also happened to be very bright. Sadly, that didn't help me to get out and practise talking to my peers, and in hindsight, I really wish someone had helped me much more proactively to develop my social skills at an earlier age as it would have made such a huge difference.
One of my proudest moments as a parent has been watching my dd "coach" another child in how to get along better with her peers. The child in question was getting excluded in the early years of secondary school because the other kids found her intensely irritating. DD is very empathetic and didn't want to be mean, but also found this child very difficult to be around. The child's mum thought the issues were inevitable because she was very bright and therefore her peers couldn't relate - believing that my dd was kind to this child because they were "on the same wavelength" and not because my dd pitied her. DD concluded that the child did not have the self-awareness to recognise when she was behaving in a way that others found annoying, so she took it upon herself to talk to the girl - as kindly and gently as she could - to explain why others were reacting as they did. They had several conversations like this, and eventually came up with a code word that dd could use to alert the other child when her behaviours were starting to alienate the other kids. Credit to her, the other child took dd's intervention in the way that it was intended and she heeded the advice. Her relationships improved significantly, and a few months later, she wrote the loveliest card to thank dd for helping her.
As an adult, I have friends who are academically brilliant as well as friends who are academically very average. All of them have other qualities that I value much more than their intelligence. There is no reason why children can only be friends with their academic equals either, and we do them a disservice in thinking that this is so. Sometimes, a little intervention in the early years to help children develop better social skills would prevent a lifetime of misery, but time and again, I see the assumption that social difficulties are inevitable getting in the way of that. We owe it to our kids to smash that myth.