Taxes are on earnings though, not revenues (you could be unprofitable and as such, pay no taxes).
Question: so are you suggesting then that just because a company's revenues (I think you mean "earnings") have exceeded X, that they should be completely broken up as a company?
Yes. But I meant revenues. If we want companies to become smaller, taxing their revenue progressively would compell their owners to split them up into independent entities. Think about it as a progressive VAT.
If you can rake in billions using a team of 50 people, that is great, and should be allowed.
Also, a company like Apple should be allowed. What should not be allowed is for Apple to own its entire supply chain (which would not be possible if company size was limited by number of people).
Consulting businesses are literally in the business to resell their employed talent. Their "product" is their employees.
As such, they type of business by its very nature have a disproportionately large number of employees. E.g. Accenture employees 700,000 people, Tata Consulting 600,000.
How would you measure “size”?
EDIT:
What do you mean by "cap" then? Would you force the company to be broken apart into smaller independent companies if it exceeded whatever cap is defined?