Authority or No of pages or all other factors are secondary.
What is more important is assessment of our goals.
Why do our website exist?
How rich content we are building? Are we sounding like subject matter expert?
Answers for these questions are more important than one page or many page?
Page rank, Page authority, Domain Authority these all are metrics as far as we are thinking about google ranking.
Ultimately one page or many pages we are building website for human being.
First purpose and then analysis. Reverse is not possible.
SAMEER