Conversations are now encrypted end to end. Since as they say Whatsapp has no access to the messages, and they earn only from data mining, how will they earn money? 
                 
It’s an interesting point.

Notice that since their last move WhatsApp can’t read messages content anymore, but they can still observe a lot of plain metadata :

• numbers <-> real names.
• every group description & image.
• every message timestamp, length, and status (missing, delivered, read).
• every conversation participants.
• every muted user / group.
• online users and timestamps (when everyone’s online).
• hesitation in message writing (they still know when you are actually typing before sending a message).
• objects types (picture, location, video, etc.)