Do copper or copper-clad steel ground rods disappear with time?

After 37 years, does mine need replacing?

When I put in my first burglar alarm, 37 years ago, I put in a ground
rod to ground the system, and iiuc reduce the chance of lightening
damage. (Nonetheless, after about 20 years, when I was leaving for
work, there were wisps of smoke coming from the keypad/control usit, and
it never worked again. ;-) I have a new alarm now, grounded to the same
rod, but something told me the rod was gone. The top of it is still
there so maybe I dreamed it, but is it likely that the part above ground
is there but most of it below ground is gone, and needs replacing?