That's a really good question! The answer is simple; we never did, there have always been taxes.

Before coinage was invented (supposedly by the Lydians in around 700BC), taxes were paid in kind. The ruler would send his tax collectors around, and they would take away some of your harvest or livestock (or maybe a daughter or two, to be sold into slavery, if you had a poor harvest).

Before the Neolithic Revolution, where we (mostly) turned from hunter-gatherers to settled agricultural types, there were still taxes, just not called that; tribal elders and family heads took what they wanted, and made sure that any surplus was distributed fairly (or at least, what they thought was fairly !).

So there have always been taxes, it's just that who takes them and what they take has varied over the centuries !

But on a more serious level, throughout history, most taxes have actually been on trade or the assets of those with enough goods to be worth taxing - income taxes as we know them now are a relatively recent invention. The church got in first on that, with the idea of the tithe....