I guess you might be right. For example, here is a semi-official answer on how Google makes money out of Google Docs: https://www.quora.com/Does-Google-Docs-an

I guess you might be right. For example, here is a semi-official answer on how Google makes money out of Google Docs: https://www.quora.com/Does-Google-Docs-and-Drive-generate-any-revenue-for-Google https://www.quora.com/Does-Google-Docs-and-Drive-generate-an... It's not unlikely that in this case they use the more traditional business model of having the free tier do the marketing for the premium option.