I think online relationships are destructive forces. The function of a conversation is to employ a process to somewhere - but when the function itself is the process, then only one thing is guaranteed: disappointment. What I mean is that if all you can look forward to is further correspondence over mutually exclusive lives, it is easy to feel even more alone than before. Relationships are vectors where one shares experience. Some may take this as a conversation, but there is a backdrop within these dialogues. You may be walking around a city, or eating in the park. There may be a festival to attend, or a board game. In online realms, there is little memory to weave together; there is little to bask in if there only are diplomatic islands disclosing what the water is like on their end.
Social functions are far more than words. A fact somewhere states that around 80% of our relations take place in body language. There are many nuances that simply cannot be shown in texts or voices - goes to show just as OP mentions that they have lost so many people to inane things that a simple expression could clear up.
Not only are these things lacking so much on the connection front, but also these things chip away at your personal time in the form of notifications. Inevitably, it is quite rare to report on anything else BUT the state of the water. That is, the exploration of the other, mutually, leads to an end. For rarely does both in correspondence take time to actually live. The lifestyle necessary to entertain online relationships usually, through unfortunate circumstance, calls for a benign half-presence. This means a lack of personal growth, and a limited view of curiosity. It is often why many people shed themselves of so many others, for it’s unsettling to be even remotely aware how much stagnation has taken place for either party.
In the event both in correspondence do take time to live, it then seems inevitable to notice how online communications hurt their full-presence lifestyle. To always be in finger-reach evaporates things to catch up on. It makes things confusing. When do we get a break? Where is the divide between friends and myself? Either one becomes hard to reach and hurts their online friendships, or gives up in being in the world and double downs on finding a quasi-fulfillment in talking about the water for the hundredth time.
The online friendships you crave are far more likely to fail, and the sincere connection you seek is rarely found in online communication.
Far more likely to fail because of as you described. The complete insignificant barrier of entry for the average internet user nowadays. I scroll through scattered forums and wonder why do I still have faith that some post worth reading will crop up? And if it does, when compared, would not a book more likely preclude dissatisfaction? For all printed words have the same auditing, and all authors know what it means to name the work after yourself.
As for sincerity, it is easy to mistake honesty and words for good intention and action. Take for example someone repeatedly saying “I love you.” If they genuinely did feel that, would they not instead show it through their actions? This is a chief principle of anyone you come in contact with. And the irony is, for online relationships, all one can do is say I love you. Repeatedly and without feeling. Without feeling? Well, have any of you ever caught someone on the phone doing something else, like doing the dishes, while you were divulging something vulnerable? Your thoughts aren’t really priority, is what was conveyed. That feeling of betrayal that could follow is impossible with online chatting, since it is asynchronous, but rest assured most of the indulgence one does in conversation is only but a part of a circle of actions chronic internet users do.
The half presence described does not just mean physically, it also means even to those you talk to. For the stream of someone’s words eventually appear only as words, and as you become more “of your self” and exposed, the less you can easily remember there is someone on the other end. Everything is easy to interchange. Even the posts you read online. Are these your words or mine? Why value my words more dearly than a friends? You aren’t you say, but you still read this, no? How can one begin to profess loyalty to an online friend if you share the same actions among strangers? How is an online friend different from an online stranger? The amount of time you could put in seems negligible, since, as shown earlier, the time is nothing. There is no return on investment, for there are no memories to invest in. Mutually exclusive lives. I suppose the only distinction is how much you know each other’s story - but this seems to be more of a voyeurism than of a concern for another person. And how painful it is to genuinely care, among either wolves who want your attention until no longer they find it tasteful, or among the people you love but in all likelihood can never be anything more than a pile of words.