Steely Dan-"Peg"

Digital transfer technology was still in its infancy
when the transfer of analog recordings to CD were first
making strides in the early to mid 80s. A lot of these
old digital transfers were recorded to digital U-Matic
videotape (such as anything done on the JVC Digital
Audio Mastering System). U-Matic was considered a solid
format for archiving at the time, but later on it was
discovered that the digital storage on them (as well as
the equipment itself) could become corrupt with age and
thus would no longer be playable. That is one
contributing factor to another digital transfer being
created.

ALso, improvements in the tehnology made it possible
for them to achieve an even better transfer from the
get-go. With advancements like Apogee filters, custom
Neve consoles, Sony's SBM process and Microsoft's HDCD
process there was a lot of wiggle room for new
transfers to be made to show off the capabilities. Some
of it was just buzz and hype (as is evidenced by the
re-use of older transfers on newer releases) but in
other instances, there is some actual improvement made.