I agree with you (though perhaps speed increases become less important after a certain threshold).
I was trying to talk about comfort difference between keyboard layouts anyhow, not the speed difference.
Given the same proficiency level of QWERTY and Dvorak/Colemak, comfort difference would be more noticeable for high intensity / little breaks / long duration activity like typing tests.
Are alternative keyboard layouts significantly more comfortable for practical tasks? I’m skeptical. (Most enthusiasts already agree they aren’t really faster).