Something that has been useful to me if to take the other people out of the equation - in my mind, at least.
Here's the thing: people react from their own experiences. People here understand and relate vividly to the picture you painted. Not everyone reaches this kind of crisis point in their lives. They have no idea how to help because their brains truly cannot understand where you are.
To use your analogy, they see you on the edge of the cliff, but they can't really understand how you got there. They don't know how to help you because there is nothing in their experience that lets them feel like you feel now. They objectively know that this kind of despair is possible, but they can't feel it with you. They can't help because they don't know how to get to where you are.
Imagine some of your people floating above you with helium balloons. They are up. They stay up. They see you, but they don't have the ability to get down where you are to help you. You see them and think, "just pop the balloon and then you'll understand." But they have nothing sharp. No tools to do that. They have a different set of tools and skills that only allow them to float. Everyone is not necessarily a bad person. for not helping.
OTOH, some people suck. They see you and just don't care. But that's them. They're assholes. Whether you fall or not, they will still be assholes. They are a non-factor, really. Because nothing you do will make them care. Even if you fall. Don't waste your brain power, especially when it is limited, on assholes.
This has become a bit rambly. Sorry.
Only you can decide what to do. Whether to climb up or let go. Please don't let other people make the decision for you.