Tony Romo defenses by year (points per game)
2006 - 20th
2007 - 13th
2008 - 20th
2009 - 2nd
2010 - 31st
Dak Prescott defenses by year (points per game)
2016 - 5th
2017 - 13th
2018 - 6th
2019 - 11th
Please convince yourself that an average 13.75 is better than an average 8.75 for their first 4 years. More importantly, Romo had 1 year with a very good defense in 5 years of his career whereas Dak has had very good defenses in half of his career. Looking forward Dak has never had a defense worse than 13th, which is the SECOND best Romo ever had in a similar time period. Three of his first five years Romo's defense was 20th or worse...
And let's get real, those defenses didn't get much better, certainly not consistently.
2011 - 16th
2012 - 24th
2013 - 26th
2014 - 15th