Just throwing money at things does not mean it gets used to actually improve them, unfortunately... The question is when you have gotten to diminishing, or negative, returns.
In my opinion the whole “throwing money at the problem is not a solution” excuse is not enough to justify maintaining status quo. Yes, I agree, governments are the worst at efficient spending. Wasted money. Unjustified spending. Corruption. Nonetheless, we have a problem that must be solved.
If the wealthy have a better idea that involves no money being spent — great. But let’s not pretend like the human cost is going to go on pause while we debate this. Impoverished children will continue to live and grow in environments that do not help them to break out of poverty. What is worse is that the odds are getting worse for them because disparities are getting larger.
To which?
I think we should encourage/require government spending on things that are actually useful (and I acknowledge that there is wide-ranging disagreement on this criterion) and fund such spending adequately.
At the same time we need to have reasonable accountability for governments doing stupid things with money, notice when it's happening, and make it stop, redirecting those funds to something productive. Whether that happens via lower government revenues or reallocated government spending depends on whether there is something productive the government can spend the money on.
The things that you list, and many you don't (quality schools, both physical plant and teacher quality, libraries, parks, clean water, free school lunches, free preventative medical care, etc, etc ) generally pass the "is productive" smell test until proven otherwise; the burden of proof there should be on critics to prove that the investment is not being done in a useful way. That said, once that burden of proof is met, action needs to take place to remedy that.
> In my opinion the whole “throwing money at the problem is not a solution” excuse
You're putting words in my mouth here. For a lot of these things, throwing money at them is a _necessary_ but not _sufficient_ condition for having a solution. If you don't fund your schools adequately they will be bad, but if you just throw money at them and it gets misused in ways that don't advance learning they will also be bad. The whole "there's a whole warehouse of unused computers in that school district" thing is not _common_, but it's also not unknown when it happens it's really bad and needs to be fixed. Both in terms of the immediate problem and the bad incentives that led to it.
So just saying "allocate money to this" is not the end of the road. You have to then make sure the money gets used sanely.