Earlier quoted context omitted.
I wonder if there would be an audience for an HTTP Basic Auth 2.0 spec. Some of your criticisms aren't exactly accurate though. "Sending a password on every request requires care to avoid accidentally logging passwords" applies to almost every login system ever made. Unless you use browser-based hashing with JavaScript, but that has significant known flaws and doesn't add much security. And "Every request needs to do…
>I wonder if there would be an audience for an HTTP Basic Auth 2.0 spec. Yes! I remember in the early aughts, IE6 would present this cool login screen [0] for (what I think, but may be remembering incorrectly) HTTP Basic Auth. I always wanted to do that, but didn't really understand anything other than making basic HTML pages. It could help improve security. It's a ubiquitous login screen that makes it really obvious…
If I was a hacker, I can use the User-Agent to know what OS they are using (or close enough). I also know what browser they are using.
I can use this information to create a custom webpage with a white background and similar imagery to look like the native browser form. If the user was unsuspecting, they might not realize it's not a separate window, and think that they were logging into the correct site.