Some people do find that as they age their toenails get out of reach.
But this limitation is not an inevitable part of getting old. The stiffness is most often self inflected by inactivity or by obesity that causes the belly, particularly in men, to block access to the toes. Still, we all lose some flexibility as our muscles become less supple with age. But the excessive tightening-up that many folks experience is far more related to not regularly moving their joints through the full range of motion. The smooth and complete operation of our joints depends in large part upon the vitality of the muscles and tendons surrounding the structures.