There are many games that are played with opponents or in groups of several. One could even say that such games constitute the majority. But there are also games that are played alone. Card games, video games, whatever. The important thing is that they are played alone, without a partner. What sense of triumph does such a game bring? But believe me, it will.
First of all, you must realize that playing alone is virtually advantageous. There is no need to look for other players or arrange a time when everyone is available. You can just play when you feel like it and when you have time. And that is definitely something to be thankful for in these hectic times when few people have time to spare.
Others appreciate not having to display their ignorance or immaturity in public. They can enjoy the game without having to worry about being ridiculed, laughed at, or having their game ruined for others. And that is one of the most important things for building self-esteem. Having fun without worrying about what others think is a pleasant experience for many people.
This also applies to people who are not very competitive and really just play for fun. These people may even feel uncomfortable entering a competitive environment, especially in games where teamwork is important. Especially in online games, such players are often the target of ridicule or subjected to comments that they should improve.
It is clear that solitaire is important to us as well. And history shows that this is not news. People in ancient times already played solo. So there is no reason to break this tradition.