Why are taxes so high though? Like in Sweden I'd pay literally 80% tax on extra sole trader income - 30% employer tax, 30% income tax, 20% high income tax.

But there is no Swedish moon base, or ultra high speed rail, etc. - where does it all go? We have higher taxes but less infrastructure investment than a century ago.

Well, Sweden has the largest wealth inequality in Europe, so I guess it goes to the friends' pockets.

Because we don't tax the people with all the money. It's why someone making $100,000 a year loses probably half of it or more to federal, state and local income taxes, property taxes, sales taxes, etc and Warren Buffett pays 3%.

There is a persistent idea that we cannot or should not tax wealth because it's "unfair". We certainly can. We do it all the time. Property taxes, depending on your jurisdiction, are either taxed based on assessed value or whatever the assessment method is correlates strongly to property value.

I can't speak to the specifics of Sweden and its tax base but in general a key problem in the developed world is the skyrocketing cost of housing. Why is this a problem? Because it's an input into the cost of everything. It makes your labor more expensive, which in turns makes what they do more expensive. I have heard getting an apartment in Sweden is rather difficult. Stories of having to register at birth and waiting 20+ years. I could be wrong.

But everywhere in the developed world has high housing costs (in terms of real income) because we constrain supply, subsidize demand (particularly to the very rich) and allow people to hoard housing.

How much detail do you need? High level expenditure breakdowns are here: https://www.government.se/government-of-sweden/ministry-of-f... and https://www.government.se/contentassets/5dc8d78159ee495fb5f3....

You can probably find more detailed breakdowns if you're really interested. But overall, most expenditures are probably in the categories healthcare, transfers to lower-incomes and education, like in most other European countries, and you probably won't find anything nefarious by looking into more detailed splits.