For all of Reeve's acting background, he landed a soap and a bit part in a film before landing Superman. (I assume he did these plays and what-not before getting actual tv/film gigs.)
For Routh's less-than-Julliardian background, he landed a soap, some tv spots, and a bit part in a film before landing Superman.
That's how I look at this. That's what I see when I look at their filmographies. Although their acting backgrounds are different, the jobs they landed because of those backgrounds are eeriely similar.