There is a skill to running a friend group which regularly does activities together. It isn't a particularly deep or study-intensive skill, but there are things

There is a skill to running a friend group which regularly does activities together. It isn't a particularly deep or study-intensive skill, but there are things to learn about how to communicate about logistics and activity-preferences. Once you learn that and are able to practice it, having friends becomes much easier. It does however also depend on meeting people who also have a reasonable level of logistical and calendar-management skill. Not everyone has this skill and not everyone prioritizes exercising it. If you have contacts who cannot unambiguously agree to meet you at a particular time at a particular pizza restaurant, you have to be willing to search out different contacts who do have sufficient skill, caring, and resources.