It is not just a matter of having elastic on the top. To have a good fitting it is important to have a good knitting. At the beginning the sock was hold to the leg using garters. After discovering new materials, the rubber were used to obtain the result. Now spandex it is the most used material.
When talking about over the calf sock it always better to have under the elastic a 1x1 ribbed knit usually called cuff. It helps to hold the sock to the leg without giving too much pressure.