That's fine. You have the freedom to disagree.
"there comes a point where the balance sheet shows more suffering than happiness, and then it's time to leave"
But I'd still be careful with what you're saying. Does it have to be 51% suffering and 49% happiness to end it all?
If there's no hope in sight, I understand, but something that general has dangerous implications. I agree, if the suffering is unbearable, I think the person is justified and I sympathize and understand their position. However, if it's something that can be remedied in the foreseeable future, then it shouldn't be taken that way.
Or, you should still wait and see if it will get better. Maybe you don't see any light at the end of the tunnel, but wait a few weeks. Maybe a couple months.
See if things change first, before you end it all. And if you decide to in the end, you have my sympathies. I definitely understand the suffering of life isn't easy to come to terms with.
But I recommend heeding a quick thought:
All suffering in our lives is caused by our sense perceptions, and our sense perceptions are caused by the impermanent states of affairs we find ourselves in. If we just let go of these impermanent things, then our suffering goes along with them. The pain might very well not, but the suffering does. There is a mountain of difference between suffering and pain.
If you are interested I'd recommend reading chapter 2 of the Bhagavad Gita, and reading up on the teachings of the Buddha Siddharta Goatama. As well as the Stoics, Daoists and others who said very similar things.
Anyway, that's my final say on the issue.