LastPass fills out my username and password on modals just fine. Tested it out on Hertz just now. If other password managers don't... then they should be improved, no?
Why should a site bother with a slower page load when an instant modal works just fine, as long as it's properly implemented?
> don’t split login across multiple pages
I've never seen this done except when it's necessary because depending on the account identifier (username) a different authentication method is used -- e.g. redirecting to your institution's authentication page.
Of course if you have a direct account you have no idea and it just seems annoying. But it is a feature, not a bug.
I'm not convinced the author has really done their full research here.