Now that would be an interesting stat... So they collect $7 trillion a year, but to collect 1% more ($70B) we would have to pay them 1/4th of that, or $17.5B -- an additional 150% of their current budget.
Hardly seems worth it, aside from the satisfaction of holding all those tax cheats feet to the fire.
Well I guess it all comes down to how you feel about tax cheats.
Given the current state of US tax law it would be a far better to simplify the rules and thus making it easier for the IRS to do its job within its current budget. Everyone recognises this, but given the political constraints it appears to be impossible to do.
Hardly seems worth it, aside from the satisfaction of holding all those tax cheats feet to the fire.