You're right, but this is known to people with lumpy income and they do not like it. There's some mitigation depending on how you depreciate or don't depreciate on a Schedule C (people with this issue tend to be self-employed) or if you have the ability to run your income through a corporation to even it out.

Even worse, individuals pay taxes on revenue, not profit, aside from a very narrow set of deductible expenses.

That's not worse.

Humans all have basically the same expense structure so taxing revenue makes sense. Corporations from different industries have wildly different expense structures so taxing on revenue would be nonsensical: you would end up undertaxing high profit industries like tech or pharma and massively overtaxing low profit industries like retail.