SSDs use memory cells that only have a certain lifetime, measured in write cycles -- each cell can only be written to a certain number of times before it ceases to function. To combat this, SSDs have special "wear-leveling" routines that make sure new cells are written to first, before already-used cells are written to. And all SSDs have extra memory set aside for when cells do eventually die, and they use these new cells as replacements. However, they only have a certain amount of spare cells.
And yes, RAM and CPUs can fail, but they are designed from the beginning for a 10-year life cycle. That's much longer than they will be actually used.