In my experience, most people are adequate at making setting-specific friendships, like "gym friends", "work friends", etc. What they struggle at is progressing those relationships to not being setting specific. Which involves inviting people places, and eventually progresses to full-blown planning, both of which are skills only learned with practice.
Agreed, I probably should have emphasized branching off of that too. Another component that slipped my mind, is taking those setting specific friendships outside their context. If you can't do that, it's probably worth spending more time on one's you can; not actively distancing yourself from them, but if you can't talk to them outside that one building, it might be difficult to build something more meaningful, or it may be a sign they're just not into you.
