EPROMS Deteriorate?

[tf95ZR1]

On the Corvette Central website I saw an ad for C4 EPROMS/MEMCALS.
I took a look. They said:

"* Originally not designed to last over 5 years, as a result Corvettes equiped (sp) with eproms
need to be replaced or flashed every 5 years to maintain peek (sp) performance.
* Eproms are newly reflashed OEM parts. The software contains the latest upgrades
that are available including running changes.
Most GM ECMs used until 1995 have an Erasable Programmable Read Only Memory (EPROM)
that stores data about the C4 Corvette engine it controls and does not lose its content when
the power supply is cut off. EPROMs also contain information specific to the transmission
and the car. The EPROM is often referred to as the "chip". The chip is sometimes located in
a removable carrier called a MemCal or Calpack. These are rebuilt factory prom chips that
include the memcal. Programmed with the most up to date program that was released from GM.
An $80.00 core charge is added and will be refunded when the original prom/memcal is returned."

I have never heard of replacing EPROMs every 5 years. What say you?