[kkirsche]

You can still separate them and have a hidden password field for a password manager to bypass the other page or pass it through to the next page.

[numbsafari]

1Password manages to handle this just fine, even without the hidden password field trick. Perhaps we just need better password managers.

[Nextgrid]

Even if password managers handle the two-page scenario you still have the delay of loading the second page. On high-latency connections this is a major problem.