Emails have been around longer than the internet - email was invented for personal communications and has morphed into a cultural phenomenon. From a productivity standpoint, many emails are just notifications sending you off into different directions. Emails are still "dumb". Watch as the floodgates of innovation open for emails.
While websites underwent tremendous innovation, emails have stayed largely the same. Think about it: Nowadays, websites host all forms of interactive content, to an extend that they become applications in their own right. They adapt to you, they adapt to the device you are using, they even work offline.
While websites underwent a firework of innovation, email merely evolved from plaintext to HTML. The only thing you can do with email is clicking links (even replying is technically just a new email). This is about to change.
How do you innovate and change a technology as ubiquitous as email? Almost every program in the world can send and receive emails. The answer: You use emails to send containers around. Inside these containers, the magic will happen:
Confidential mode lets you send containers with confidential content. You have control over that container: You can make it self-destruct after 2 weeks, you have a button to destroy that container and you can prevent other people than your intended recipient from opening the container.
It doesn't work offline. Your colleagues may stop talking to you. But it's impressive and sometimes necessary.
Programmers will be able to craft emails that have interactive containers. Their content will be generated when you open them - this will let you like, pin and share a bunch of suggested Pinterest images at once, or see all details of an AirBNB home without opening the website.
For G Suite, when you get an email about comments made to a document, you will see a live version of that document (perhaps that comment already has a reply).
Some ideas of what could be in store:
Calendar: Invitations could display the RSVP status of other guests. Also, no more "This invitation is out of date" - there may just be one invitation.
Docs: You could reply to a comment (and directly edit a document?) from within the email.
Drive: Handle sharing permissions directly from those emails asking you for access.
Google+: Like and reply from within the email notification, and see others' comments.
Meet: Join Meets from within the email, or see the "ante room" if the meeting has already started, including who is already there.
Sheets: Why not the ability to send snippets or graphics that always reflect the latest status of the document?
... and this is only the beginning - I'm merely reflecting on two types of "containers".
... because it makes email more complex and less static. And outside of G Suite, it will be used for delivering ads. Still, I welcome it as a tool to be more collaborative and get more done, faster.
As with every email innovation, this will need to be supported by email providers and apps, or people will see the static version. Gmail, Yahoo and Outlook.com are already supporting it - another reason for you to switch from iOS Mail to using the Gmail app.
All of this is not to say that simple emails are going away. While I agreed we will write ever less email, I apparently stand corrected about receiving fewer (email) notifications. We will likely receive more useful notifications going forward and get more done without leaving the inbox - so this is good. And perhaps it means less notifications. Thank you for reading!