This is a business opportunity to provide services at a minimal cost for people. Say 1$ per month per service.

Email - 1$

Calendar - 1$

Document Collab - 1$

Each addon a calculated minimalist approach to each. I still recall what gmail was when it was invite only back in the early aughts. I would still utilize that gmail client. I do NOT need gmail as it is today. And I would certainly pay 1$ per month for that service.

(E) For a minimal and basic interface, along with a low cost, I and certainly others that I know who are tech illiterate, would pay that low cost for simplicity + privacy.