If a guy had a huge attic and built a 80 meter "CAGE DIPOLE" out of 2
foot
diameter continuous aluminum flex tubing.... would it work better than a
cage dipole built of multiple wires?

What is your definition of better? Certainly wider BW, but the loss is
already so low, that the improvment there would be infinitesimal.
How does this relate to the Subject - Big Loop?
Dale W4OP

As Dale mentioned you will only gain a wider bandwidth for the frequency its
length is cut for.

Instead of a single linear dipole think about constructing a very large
horizontal loop around the perimeter of your roof.
The bandwidth for a 1 wavelength (90meters) H-loop is continuos from 90
meters all the way up to 6 meters. The performance is identical to a dipole
at an equal height.

Lots of info about large horizontal loops on the web.