At one time I wrote about the Pareto principle, but it seems to me that in this situation where people have to decide to continue their efforts or not, with respect to someone, it works in the 5/95 ratio..
People are more likely to refuse to support others without seeing real change. And rightly so.
I agree that a valuable and scarce resource should not be wasted without believing in a successful outcome, and I agree that resources should be redirected to where they can have maximum effect.
But, on the other hand, we do not know what a person has inside when they have a critical moment, a "bifurcation point," when just one more word from us can change them and their whole life. As the Bible says: "In the morning sow your seed, and at evening withhold not your hand, for you do not know which will prosper, this or that, or whether both alike will be good."(Ecclesiastes 11:6).
It is subtle and individual, and one must have wisdom and faith to do right in each individual case..
If the million words over years didn't make the difference, it is unlikely one more will. The next word is statistically more useful used elsewhere.
In my opinion, it is about relationship collaboration and while it is never 1:! reciprocity, there has to be some mutual benefit. the good feeling of helping someone can be felt by helping anyone, so in regards to resource allocation, it is very much like a marketplace of products, where people are looking to maximize their buying power (at least in their head) rather than throw resources away.
It also comes down to the type of relationship that people have and online, those relationships are tenuous at best and, the real situation is largely hidden.