Software does age. Security ages, network protocols age, human related configs age (timezones, for example).
And that's besides tribal knowledge that goes away as people leave or retire.
And that's besides tribal knowledge that goes away as people leave or retire.
Its not being stuck between a rock and a hard place, you just need strong management that understands that changing whole systems is never a good idea without clear benefit, other than "technical debt" which is such a bad term for reliable software. Software doesn't age, im not sure how software engineers don't understand this, or maybe they do and want to write more s/w.