Because email is a decades old technology that, thanks to its decentralization and such a wide spread usage, is impossible to improve.<p>I highly recommend this blog post about a guy trying to make its own email client and failing to do so miserably because emails are such a mess : <a href="http:&#x2F;&#x2F;www.slate.com&#x2F;articles&#x2F;technology&#x2F;technology&#x2F;2015&#x2F;02&#x2F;email_overload_building_my_own_email_app_to_reach_inbox_zero.html" rel="nofollow">http:&#x2F;&#x2F;www.slate.com&#x2F;articles&#x2F;technology&#x2F;technology&#x2F;2015&#x2F;02&#x2F;...</a><p>Edit: removed the Pocket redirect from the URL.