According to this 2001 article, Riverbend went to Springfield because Eugene didn't want them anymore. 

 "Frustrated by Eugene's rigorous land-use measures, Catholic health system officials are sticking by a plan to move Sacred Heart Medical Center one town over.

 "But the Register Guard has come out on the side of the hospital. In an editorial this week, the newspaper coined the term 'regressive majority' to describe the city council members who were setting the hospital on a tough regulatory slog."

"In a statement issued last week, PeaceHealth officials say that the Springfield site 'offers the greatest opportunity to build a new facility that meets the original goals and can be completed in a timely manner.'

The land-use process is 'simpler and clearer' than in Eugene, said the statement,  

I'd think Mckenzie-Willamette might have had similar thoughts.

http://www.catholicsentinel.org/main.asp?SectionID=2&SubSectionID=35&ArticleID=6373