Just because there's a limit of 200 friends doesn't mean you have to add that many. Everyone's play style is different and having such a large ceiling for friends is to help emphasize that I think.
I have 60 on my friends list, most of which are from trainers in the two decently large groups I raid with. I may not know all of them by face but figure I'm likely to raid with them at some point, so working to those rewards will help.
I have a small handful of IRL friends on there for the obvious reasons.
What I don't have are any randos from the internet who I have zero chance of interacting with IRL - I get enough gifts, I don't need more. Especially with the daily gift opening limit.
Everybody plays differently and will friend varying amounts of people for whatever reasons. Some people may have alt accounts, bringing some obvious factors into play there. Some may friend as many foreign people as possible for Pilot badge bait. To try and make a "perfect breakdown" seems silly because it won't fit everyone single player's needs. This isn't a situation like DPS where there are objectively right and wrong answers, there's much more nuance here. What's perfect for someone may be completely useless to me.