> Consider what you might choose to do…

Emphasis on might.

Evidence suggests "a giant boat and some helicopters" is the more likely result.

Which 30% are you talking about? Taxes? If so: From what do you build things like infrastructure?

Well my taxes go to roads, healthcare for people who can’t afford, schools, and the fire department. I would consider those public goods.

The billionaires out there are being revealed as paedophiles quicker than they are solving world health problems.

I’d prefer not to rely on them.

> Consider how many more philanthropists would be created by returning this 30% back to individual discernment.

Many, many fewer than you assume.

Libertarians like to make lots of good-sounding promises to justify their favored radical policy, but it's bullshit and the promises don't pan out when tested [1]. By that point, the libertarian has gotten what he wanted and moved on.

[1] Or their policy was already tried and already failed, e.g. https://news.ycombinator.com/item?id=46876387, leading to reforms to fix the problems that they're now mad about and want to undo.

A lot less because they'd be dead from easily preventable diseases in their water supply?

Is there evidence that it happens? And that it serves the public good, not the personal interests of the wealthy? Do we need another $100 million given to a health program accessible only to the wealthy, or funding for public health? To a business school or art museum, or to arts programs for public schools?

Philanthropy is anti-democratic; the people don't choose what is important to support, the wealthy few do. You can see that in the relatively poor public goods in the US, which has much lower taxes relative to peers.