Current reading behaviour is somewhat different and tends towards scanning/skipping because the breaks between pages are much less significant with a resume on screen.
Are you citing something or just generalizing from what you've seen?
(there may be other factors at play though, as candidates who submit paper resumes are obviously different from candidates who submit electronic resumes; in addition most of the paper resume studies are now historical (pre-2000) so there may also be a time factor involved)
Also, the '1 page' rule of thumb is not a hangover, it's a great rule - one physical page happens a good amount of space to show your experience, but not have too much information that it can't all be read quickly. It's a positive limitation.