Because it is simple, reliable and it was early

It's an interesting question.

Email has morphed into something quite different from when it started, and was a good way for humans to send messages to each other. That use case has mostly been supplanted by SMS, whatsapp, the social media app of the day, etc.

These days, it's really only used for that purpose mainly inside organizations, and "public" email seems to be overwhelmingly marketing material and automated notifications, with only the sporadic message from a human being. It's kind of functioning as what people wanted RSS to be.

The cynic in me would say that it survives because it is an effective tool for marketing, and the subscriptions / recipients are controlled by the sender.

It survives because it already solves the basic problem well enough. You can reach almost anyone and communicate without needing to join a platform or build a network first.

It’s simple, open, and relatively low-pressure compared to most modern communication tools. A lot of newer products try to improve it, but often they’re mostly adding layers rather than solving a fundamentally missing capability.

Email's resilience is almost paradoxical — it's the least "designed" communication tool we use daily, yet the most durable. Slack added presence and speed. Notion added structure. And yet none of them replaced email's core role.

I think the reason is that email is fundamentally asynchronous and unbounded — you can send anything to anyone, with no shared platform, no mutual agreement required. That's not a bug, it's the entire point. Every "better" tool that replaced it added friction by requiring both sides to opt in.

Interestingly, even AI hasn't disrupted it — if anything, AI has made email more valuable by making it easier to write well and filter noise. The protocol survives because no single company owns the incentive to kill it.

I always find it funny how many things have tried to replace email and none of them really stick. Slack, Teams, Discord etc are great for real time work but when something actually matters people still send an email.

It’s ugly but it works and everyone already has it.

Probably because email is so deeply important for the modern internet everyone has a interest in keeping it working smoothly

Because it doesn't rely on a single point of failure like centralized services. (You forgot "Ask HN:" in the title.)

Because it is decentralised. Google tried to take control over it with gmail but despite doing well, it can never control it.

Also, it is your digital identity, there is no substitute.

Don't get me wrong, the entire thing is primitive and outdated AF, but as long as it works and can handle the traffic it is getting, it's not going anywhere.

It works.