I remember sitting in a class one day and hearing that there would always be wingtip vortices on planes, and wondered if that could be solved by looping the wing around (to where it almost looks like a biplane).
I wonder how many other ideas are being sat on because people don't realize its significance or have the resources (such as time or desire).
Another old option for eliminating such issues is to put the prop in a case, like a jet ski or most modern military submarines. Or just eliminate the concept of tips and turn the entire case.
https://en.wikipedia.org/wiki/Stipa-Caproni
Even newer patents should cite this research:
We can't banish them, but you can do things to reduce them, the simplest of which is to move the tips further apart (i.e. lengthen the wings.) Everything about airplane design is a compromise, however.