FLASH, CPLD, FPGA - Future of repair?

Hi together,

looking at modern products repairing them becomes increasingly
difficult. Due to the massive use of programmable logic and
software residing in flash memory - there are lots of componentes
which can not be checked or replaced - even if they are known
to be defective...
Sometimes even the original manufacturer is not able to supply the
right chips to fix the problem. My question is how the know how
residing in such chips can be saved prior to their death?
For software there exists an archiv (bitsaver.org) to preserve
it, but how e.g. on fuse-lists of FPGAs?

Logic devices are hard to read out without the appropriate programmer.
Even if they are in a socket the protection fuse my prevent
reading... Is there any experience how long EEPROM-based FPGAs and CPLDs
really keep their programming?

The actual reason for my fear of these components is that
test equipemt, especially high quality one like tektronix or agilent,
always was an investment for many years - who is not happy about
his working Tek535 on a cold winter day? Recently there came up
relatively many of high end oscilloscopes (545xx) on eBay with
comments like "out of service", "agilent refused to repair",
"not serviceable". Since I own such a device, I suspect the
ALTERA EPM5128 or the soldered in flash memory beeing the problem.
Honestly speaking I was shocked that HP/agilent oscilloscopes are
"not servicable" only a couple of years after they have been
discontiuned :-(

Thanks god, my 54542a still works...