I would argue that authentic close friendship is hard to find and is somewhat of a scarcity.
You can find a lot of people who have transactional-style friendships or business friendships.
The trouble with that however as is the trouble with anything that's transactional socially is:
It doesn't last. It doesn't last because it isn't built to last.
Authenticity can also shift between time and age into more transactional-based friendships.
This typically tends to happen as people get older and go about their own lives making their own decisions, often accidentally stumbling along the way. It's normal and quite common, but also sad and quite unfortunate.
My closest friend is 37, and is on disability after handful of failed suicide attempts.
So he no longer works. His mother takes care of him. I'm reasonably sure he's suffered some sort of complex internal brain trauma from his suicide attempts, because his neuroticism has increased over the years.
I love the man, I do. He's like a brother to me.
But also he can be very trying, very challenging at times.
I can definitely understand his mothers frustrations as equally as I can his with her.
He doesn't work., doesn't go out, doesn't socialize much due to his agoraphobia and social anxiety.
Yet simultaneously, he's also cognitively one of the smartest people I've ever met.
Being of Socratic philosophy, thinking like an architect, with mild to intermediate computer science comprehension.
He is absolutely not useless.
What he is, really, is sick of other humans honeysuckle.
And I really kind of can't blame him.
Introverted misanthropy is sort of the mutual foundation of our friendship.
Known him for like 12-ish years.
Other than him, I don't really see anyone in person outside of my family.
I've got another friend I've had for decades who, unfortunately like the above I stated has shifted from authenticity into a transactional-style friendship. What I learned is that people who go through that, that unfortunately befalls them because of their lack of developmental impulse control and/or lack of focus. He can focus, but he has no impulse control. So the result is, that by the measure of his own social corralling, he can't stand up to his own standardizations due to ego.
In life, The Master has Failed more times than The Student who refuses to even try.
And in Truth, that is because Failure itself IS The Master, it IS The Teacher.
It's easier to get hung up on a feeling, than it is to extrapolate what that feeling actually means. The subtext of subtext itself, or the meaning behind feeling, is basically the bounceback off of the walls of your own mind. But because it's subtextual of even the subtext itself, people don't usually pick that up.
So because they don't pick it up, some never learn it, some polarize into denial due to ego, some have to be forwardly told it before they actually really realize what they're looking at (because how do you know what a vessel looks like if you've never seen a vessel before?), and some people are just like: "Eh fresia it, TL;DR."