While most SEOs believe larger sites rank better in Google, John Mueller of Google said on Twitter that is not by design. He said just because there may be a correlation of big or large sites ranking better in Google, it doesn't mean that is designed into the search ranking algorithm.
John said:
Correlation... I don't have statistics on that (& what is "rankings" anyway). Definitely no designed connection.
— John ☆.o(≧▽≦)o.☆ (@JohnMu) September 6, 2017
He then added that anyone can write a script to make millions of pages and that doesn't make your site awesome. Focusing on the pages you have and making those pages better can make your site awesome, John added:
YES! Focusing on fewer pages can lead to #awesomeness. Any script can make millions of pages, only you can make great pages.
— John ☆.o(≧▽≦)o.☆ (@JohnMu) September 7, 2017
In fact, just the other day, John hinted that some sites with tons of content can be seen as spammy if designed to be done just to rank for more keywords:
Big sites have lots of content, that's fine. It sounds like you want to "create" millions of pages, which sounds a lot like spam though :-/
— John ☆.o(≧▽≦)o.☆ (@JohnMu) August 31, 2017
The thing is, the more pages you have, the more chances you have to rank for more keywords. The issue is, Google cares a lot about quality, so if those pages aren't built well and have unique and compelling (awesome) information, then Google won't rank it well and might not even index them.
Forum discussion at Twitter.