If enterprises had their revenues capped at 100M$/year (and anything above that taxed at 100% to enforce it) there would be so much competition we wouldn't have time to think about this.
I like the idea of corporate tax being a function of size (to reduce monopolies) but I suspect a policy like yours would simply result in lots of very ‘friendly’ companies with revenues of 999.99M/year.
That would be perfectly fine, in the end the power to do so would be less concentrated and less centralized as much as it is now.