Our apple tree wasn't doing much of anything (it barely even ever flowered), so I finally cut it down and bark grafted 3 different varieties onto it - Liberty, Ashmead, and Cox Orange Pippin. These should all be able to pollinate one another. We also have a Honeycrisp tree nearby that should benefit from this, too.
Nice! Don't see enough of people taking advantage of in-ground root stock. This works wonders with stone fruit and citrus as well.
Yes! Figured it was better than getting rid of the tree.