I'm very confident that your method would only make things look better for Ruth. Trout has other players at his level in any given year (Miggy, JD, Harper, etc.), but Ruth was so far ahead of the rest of the league that he changed the way that the game is played. He was also a high level pitcher. To me, that adds a lot to his resume.
http://www.fangraphs.com/leaders.aspx?pos=all&stats=bat&lg=all&qual=0&type=8&season=1920&month=0&season1=1920&ind=0&team=0&rost=0&age=0&filter=&players=0&sort=5,d
There is no way to quantify the difference between eras. I obviously know that Trout is 'better', but there's the access to nutrition, exercise, legal performance enhancers, etc. In 50 years, people will be saying the same thing about Trout.
The greatest player can only be compared to the best competition available in his era. Babe Ruth is clearly that player for the moment. Besides, it's not even clear that Trout is better than his modern counterpart, Barry Bonds.