Sometimes a nodule is in a place too difficult or unsafe to biopsy by needle or endoscope. When that happens they will do a resection to complete a biopsy.

As for the ground glass nodule, they cannot biopsy something that is not solid. Many disappear by themselves others may take years before they start to become solud (if ever). I have ground glass nodules that were present on a CT 15 years ago that are still there and unchanged.