I do think this sort of question is really about something else. There are many people who are single for long periods of time, or even for life, whether out of choice or out of bad luck. People in this situation may feel abandoned or even angry when their friends pair up and inevitably reduce the amount of time they can dedicate to friendships. Neither party is in the wrong, really, it's just a natural process that sucks for the single friend.
So what are the options for perpetually single people to receive love and care as well on a regular basis, or to feel that they are also someone's priority?Unfortunately, in our atomised society, there aren't many options. This is something worth thinking about. We can and should be, as a society, more open-minded to different types of communities, households etc. that are not exclusively based on romantic relationships or blood kinship.
Of course, that's not easy to think about or design either, and there's high potential for tensions or even starting a cult (ha), but there are some studies that show co-living, intentional communities, co-housing etc. can bring an increase in happiness levels. However, a person would still have to move on to a degree from friends who choose the Western individualistic family unit model, and try to find like-minded people. So... you can't freeze in time the friendships you had when you were 20, and the importance you had for your friends then, either way.