I think friendships (and relationships in general, but maybe more-so friendships in particular) change and evolve and shift over time. I think that's natural of the relationship. You might be really close with someone, and then over time separate for whatever reason whether its family obligations, moving away, busy with a job, etc. This is even more true when you get older and older.

Depending on your age, the truth is, friendships don't necessarily hold much water as they did when you were younger. Like "besties" just don't really happen after a certain point. This is an observation I've made throughout my life. My parents didn't have best friends or even close friends, but they would still have get-togethers or dinner parties or the occasional lunch with a friend. Their friends usually consisted of their coworkers, in which case they were more like acquaintance/political workplace friends as opposed to best friends.

So my point is that friendships are cyclic in nature and they tend to change with time. You should only focus on those who you enjoy hanging out with, and once it turns into drama, let it go, it's not worth it.