I am more of the @ChickenyChick and @Bluebird3456 way of thinking.
Many people are very wrapped up in themselves at the moment, and also strangely busy if working (even from home) or have young kids, or elderly relatives. WFH is draining and can leave you not wanting to communicate.
Someone mentioned not liking to ask how people are. I have a friend with Covid, the long-lasting exhausting one. She seems to prefer light-hearted chit chat, and doesn't say much about how she is, even if asked. I let her know I'm thinking of her, but not constantly, I hope she doesn't think I don't care.
Sometimes friendships do run their course, but often it's just that they change anyway, as we get older and have more responsibilities.
Some people are busy bonding with neighbours, as they can actually see them! Or binding with school parents over homeschooling, or whatever. Everything is different at the moment.
Sometimes I get those feelings of why aren't I more important to a particular friend. But I let them go, as they're mainly just insecurities and not a reflection of friendship.