I don’t have much issue with email as a technology. It does what it needs to do, and does it well. The client side software is what hasn’t budged in years - Search barely works, files and attachments are cumbersome, and spam is still rampant.

It would be much cheaper and easier if users weren’t centralised under a few big providers that prefer to bar any and all access to said users if you’re self hosting, making it almost mandatory to use a private service.