At this point browsers are more complicated than the operating systems we had back when browser+mail was the norm. And I bet Gmail.com running in a modern brow

At this point browsers are more complicated than the operating systems we had back when browser+mail was the norm. And I bet Gmail.com running in a modern browser is more complicated than a mail client from that time. As such, browsers are now an app platform. They don't need to ship with prebaked apps like mail. They need APIs like a powerful runtime, visualization layer, background services and notifications... and they have them.