All money spent is voting for allocation of resource. Sometimes there is too much money fighting the same goods in which case it may not be a good allocation of resources. That money can sit to become more money.
At a societal level, immortal wealth is incredibly bad.
At a personal level, because wealth sitting still, having 4% pay for the overhead of maintaining the 96% and then using the pennies left doesn't accomplish much of significance.
Nobody allows money to sit. People deposit the money into banks. Due to fractional reserves, that's equivalent to loaning the money out so that others can efficiently allocate it instead. That's how money becomes more money.
Charities that aren't actually spending money to do good are just banks in disguise. Banks that don't pay out interest. Why would anyone donate even one cent to banks?
You can always wait another year. And then another. When is it time? 50 years? 100 years? "We will maximise good by donating it all in 1000 years" is questionably not a charity at all; it's just a massive pile of money that isn't used for anyone but paying the people sitting on it.
Even if you trick-feed donations to charity over 100 years, the sums may be insufficient to reach a usable scale.
- A big investment in research.
- A concentrated push to vaccinate against a Disease so it goes away for good.
- An infrastructure investment that lifts a community out of poverty.
These themselves produce "good over time," perhaps even faster than the money in the fund rises in value. It's a balance, but immortal trickle donations are likely quite far off to one direction of that scale.
All money spent is voting for allocation of resource. Sometimes there is too much money fighting the same goods in which case it may not be a good allocation of resources. That money can sit to become more money.