Homemade Memorial at La Vista Memorial Park

There are a number of homemade memorials at La Vista Memorial Park in the unendowed section of the cemetery. Here is one for Margaret E. Miller (no relation of mine):

There is a homemade cross with Margaret's name, birth date and death date, anchored by a concrete brick, at the head of the gravestone. The concrete gravestone presumably lies over the coffin, and has Margaret's name, birth date, death date and relationships on it, plus signatures of loved ones.

Unfortunately, the gravestone has already cracked in several places. I wonder which will last longer - the cross or the gravestone?