But filling a leaky bucket does have an impact. You just have to fill it faster than it empties. Which is probably your point.

My point is different. Study after study shows that below a specific floor spending has almost no impact on educational outcomes. The correlation is such that you can both determine that there is likely no leak and also that it has no effect.

The stuff that does have an impact is much harder to move the needle on though so everyone just scapegoats funding instead. Stuff like building up the nuclear family in an area, increasing income mobility, and holding parents accountable for child outcomes do have a measurable effect but are politically intractable today.

So theoretically if your spending was hiring more and better teachers and better HVAC and more/smaller classes then spending would and has experimentally been verified to have an impact. Especially if you also paired it with getting rid of teacher who don't meet the bar.

But as a practical matter that is not what happens when a campaign to increase funding for a school happens. The problem is not insufficient money, the problem is not enough skill and political will in how you spend the money.