The problem with this is that it's not as convenient as passwords and people hate things that are even slightly inconvenient.
Typing a username and password is very fast assuming that you remember them both (even faster with a password manager).
Now you have to log in to your email every time you want to log into any website. This is especially inconvenient if you are a webmail only user. Or you have to get a code sent to your phone which you have to retype if you want to use the website on a different device.
What happens if your email provider goes down, or your phone isn't working?
The problem with this is that it's not as convenient as passwords and people hate things that are even slightly inconvenient.
This is generally true but I wouldn't go that far.
One example of something that is more than 'slightly inconvenient', while being introduced globally fairly recently, is captchas. Sure, nobody likes them but it isn't like people have boycotted sites that have them.
(another example would be requirements for longer passwords with digits and mixed letters in them - a requirement that was mostly non-existent 10 years ago)
Sure, email authentication is probably more inconvenient than my examples, but you can definitely make improvements to it (a browser extension similar to those used by password managers for example can greatly reduce the inconvenience) if it becomes the standard.
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The problem with this is that it's not as convenient as passwords and people hate things that are even slightly inconvenient.
Typing a username and password is very fast assuming that you remember them both (even faster with a password manager). Now you have to log in to your email every time you want to log into any website. This is especially inconvenient if you are a webmail only user. Or you have to get a code sent to your phone which you have to retype if you want to use the website on a different device.
What happens if your email provider goes down, or your phone isn't working?
This is generally true but I wouldn't go that far.
One example of something that is more than 'slightly inconvenient', while being introduced globally fairly recently, is captchas. Sure, nobody likes them but it isn't like people have boycotted sites that have them.
(another example would be requirements for longer passwords with digits and mixed letters in them - a requirement that was mostly non-existent 10 years ago)
Sure, email authentication is probably more inconvenient than my examples, but you can definitely make improvements to it (a browser extension similar to those used by password managers for example can greatly reduce the inconvenience) if it becomes the standard.