critics indicate that the tax revenues would have been considerably higher if the tax cuts had not been made. income tax revenues in dollar terms did not regain their fy 2000 peak until 2006. the congressional budget office (cbo) has estimated that extending the 2001 and 2003 tax cuts (which were scheduled to expire in 2010) would cost the u.s. treasury nearly $1.8 trillion in the following decade, dramatically increasing federal deficits.