Income tax is an effective strawman. The only reason it's the predominant form of government tax income for the government is because of how taxes worked. Pre 1900, almost all tax came from trade, labour licenses and wealth/death taxes.
There are people in the US who increase their wealth by $1 million each year and pay no income tax because their increase in wealth was tied to assets, not increased income that year. By loss offsetting, or other evasion/avoidance measures, they can even end up paying little or no capital gains/asset taxes (which are already significantly lower than income taxes). And they aren't included in your figure.
These are the same people mentioned in the other comment reply to you, quote "A worker's salary is taxed at a high rate like up to 40%, whereas a wealthy person's gains from assets are taxed at a much lower rate like 15%. And that is if they realize the gains at all, because their unrealized gains don't get taxed at all."
If assets and capital gains were taxed in the same way (no intermingling, no loss offsetting) as income taxes, then tax would be far more equally distributed - which according to you, would be better right?
You think it's unfair to ask "laborers" pay more tax, since the top 1% already pay 45% of income tax
Let's adjust the law then and have the top 5% by wealth pay 45% of all wealth+income increase via tax, this must be fairer to you?
Basically I would agree with your argument if the practical effects were that the people in practice with the most money and secure income(from any form, be it employment or wealth/asset gain) were paying 45% of all the taxes, however that's not the case. And you are ignoring massively the unrealized gains and ability to offset losses which is available only to those with wealth, but not income. (e.g. I can't set aside my gross salary as a net loss and then use an instrument to gift it to my children a few years later with no effective tax)
The current system is designed to
A) Easily extract taxes (do it before the commoners get the net money
B) Keep assets with those who already own them
C) Shift the tax burden on to the top 20-30% of earners by income, but not wealth.
The effective tax rates you quote for the US are both influenced by this system in a way we can't remove from the data, and show anyway that your belief is weaker than the facts you originally presented (ca. the 45% figure which ignored wealth/assets).