Striaght pro-football-reference.com
TO games started:
Year 1 10
Year 2 15
Year 3 10
Roy Williams
Year 1 12
Year 2 12
Year 3 16
Difference of 5 games. That is really not all that relevant either. Starting does not mean much. Didn't Jimmy Johnson punish Michael by not starting him. He missed the first play or series or whatever, but played most of the game.
BTW the first five years of their career RW started 63 games and TO started 62 games. As someone mentioned and unless I missed it, maybe it is unfair to compare RW to TO. TO had Rice opposite him. Isn't that been part of the complaint about RW "Should have put better stats with TO on the other side". TO had Young and Garcia.
Bottom line is you can no doubt make a case for your argument. I would not say you are out in left field or anything like that, but if you want to hold those standards, I don't see how you can ever compare any player to another. Different system, different QB, different era, different draft status, different coaching, different weather, different caliber of teammates, and etcetera.
There is no perfect comparison. All I know is they both started minus 1 game the same amount of games their first five years. They both have advantages and disadvantes. Draft status, team talent, coaching, QB and so on and so forth. In the end the numbers are what the numbers are. And they are not all that different.