Are you sure?
What can't the 9-9-9 plan become a 16-16-16 plan within 5 years?
The Income Tax was instituted in 1913 with a top rate of 7.8%; by 1918, the top rate was already 77%.
Be careful what you wish for.
Your criticism of 9-9-9 applies even more to the current system
There is nothing in the current tax code that prevents Congress to from simply raising rates 20-30-50%.
This same complaint about 9-9-9 applies even more so to the current tax code. It would actually be much hard to raise tax rates under 9-9-9 since you could not hide it as a “tax on business” or “making the rich pay their fair share”.
Everyone pays so everyone knows any tax hike requires them to pay more. It eliminates the current system illusion that the poor get a free ride while the rich pays all the taxes. Those indirect taxes hidden in the current code are eliminated and replaced by a transparent flat rate
So your criticism of 9-9-9 is completely without rational merit.
Your reply makes no sense - how is what you’re talking about different from what we have today?
Going to a 9-9-9 plan would be a win for at least the duration of the Cain administration - and it would do a huge amount to lower real unemployment and get the economy going again.