As a speech-language pathologist, I work with students with language and/or speech delays who may have other disabilities like autism, ADHD, or more commonly specific learning disabilities.
If I had a dollar for every kid who told me they did not care about people, I would be semi-rich. That's not to say that every kid has this perspective, but quite often I hear kids talk like this when I ask if they have friends at school or what extracurricular activities they are involved in.
Many kids who keep to themselves and say they don't care about making friends say they feel different from their peers. Many of my students who feel different from others say mostly one of three reasons:
As a result of feeling excluded, they have developed a "go it alone mentality" and pull away from others. They go to school and sit alone or may have a friend, but if that friend is not there they will say to themselves not join in with others. Because many schools practice an inclusion model, these students are in general education classes. This makes it more likely that their self isolation can go unnoticed. They don't study with others and fly under the radar because there are often not behavior problems.
I have found many kids who self isolate seem to believe they can go through life this way and that they don't need others. I tell kids in this situation that it is understandable that they feel the way they do, but it is their responsibility to practice connecting to others for one important reason - because they need them. Everyone feels some level of insecurity no matter how confident they look. We are all trying to fit on one way or another, and it is normal to feel inadequate. I try to remind kids that they will have to work with others in groups to achieve goals in life.
For example, in life it's necessary to work on class projects starting mostly at the secondary level through the college level and it continue in the work place. Many kids are surprised to learn they have to work in groups in their future jobs. It is good to begin the process as early as possible so they can get good at it with the additional benefits of learning something from other people. It's a good idea for kids to participate in as many extracurricular activities as possible to find out what they like to do to figure out what brings them joy as their happiness is their responsibility.
I have been able to convince many students to talk to others and explore their interests through participating in things they thought at first they first thought they did not like. It was not easy, as many kids say they don't want to do be in a group and I did not convince everyone, but was always happy to hear someone tried participated in an activity years later. The key is to encourage them to engage with others, join groups, and explore what they like even though it looks like it is falling on deaf ears. Parents can benefit from talking up connecting to others. If you find your child is someone who does not want to make friends or move away from their video games, I encourage you to find out the activities going on at school and encourage your child to participate in band, chorus, sports, and/or different clubs and to keep doing it even if you get pushback. Remember it may take time, but if you keep pushing they may come around in time.