Quite the opposite. You can't fake revenue nearly as much as you can fake profits. Examples are legion - look at any company in the US that pays 0% (or negative) corporate tax rate.

You are not understanding the issue. Revenue can be trivially made to disappear, and this is what actually happens when governments tax revenue.

Revenue is recognized as the size of a sales transaction. The number of sales transactions required to build and sell a given product can vary enormously based on the structure of the business, usually as a product of optimizing for efficiency and specialization. When you tax revenue, businesses have a large incentive to restructure their business to optimize for minimizing the number of sales transactions in the course of building the product, because revenue taxes essentially compound as a function of the number of transactions which is then a cost of business. The compounding is why revenue taxes are so low, usually around 1%. Being tax efficient lowers your costs more than being business efficient, leading to bloated and non-competitive companies.

I've operated a business under one of the few revenue tax regimes. The perverse incentives to verticalize the business structure are very real. Revenue taxes add up quickly.

To make sure I understand your point, is the argument that without a revenue tax, you're incentivised to sell as much of your stuff as possible, whereas with a revenue tax you're incentivised to maximise your margin, and this makes things inefficient for everyone downstream of you?

What about only taxing B2C revenue? Then the degree of vertical integration wouldn't matter.

It’s much easier to do that with something called a sales tax!

Isn't that more a value added tax, rather than a straight sales tax? Similar, but not identical.

VATs operate at every stage of the supply chain. A sales tax is only applied at the point of consumption.

That's kind of my point though - it ends up being charged on the 'value add' at each stage, so the vertical integration doesn't matter. X % of the final cost should still be VAT.