I have never heard of this "one page" rule. Maybe it's meant for those people who cram every detail and buzzword in their resume mistakenly thinking that if they chance on the right combination of words it will help them.

Mine is one and a half. I think it's more important that it's easy to read, if you're trying to fit everything into one page and it becomes dense or overly brief it defeats the purpose of the rule.

These rules are made up employment coaches (or whatever they're called) who need content to write about and want you to hire them for their consulting services.

A Resume is a crapshoot anyway, anyone can put anything they want in it - most of it is unverifiable until tested. As long as you have the required skillset, the important thing is that you don't act weird in the interview.