That's why we write. So we can keep our imaginary (and therefore perfect) friends with us forever.
I think it gets harder to make friends as you get older. I used to have a large bunch of people I was out with every weekend, all of us being footloose and fancy free as it were. Then we got old and had kids and life suddenly wasn't like that, and by the time your bairn's old enough for you to go out again, you've forgotten how to talk to people.
His friends' parents are nice enough but we have nothing in common. Can't do more than make five mins small talk with them. The child free friend I have has mobility issues and lives 30 miles away, the other friend has two kids younger than mine. I have an old fart for a best friend 150 miles away, another friend 200 miles away. My boyfriend also has no friends nearby or in good health.
I joined a writing group but again, all perfectly insane people I have nothing in common with beyond the writing. By that I mean I'd hate their nights out and they'd hate mine.
I used to live within spitting distance of several friends and we'd all just wander around each other's houses or meet on the hippy green in town. Great days. Some fucked up shit too, but you get that. Mostly good memories though. It was great for an introvert like me as it meant I could go or not, and nothing was expected of me; if you have to make a big mission to see one friend it gets a bit much.