Absolutely, by all means look at old code - code that has survived and been useful for a long time. It's either adaptable (Linux) or doesn't need to change or adapt much (TeX).
Do you currently use and rely on software which you expect won't be useful to you in ten years time? I can't think of much personally.
(I do use IDA Pro, which has clearly adapted poorly to changing requirements - it still has scars of the 32-bit to 64-bit transition that get in the way of day-to-day usage. I hope there'll be something better in ten years. Of course, I could buy a cheaper, "higher quality" tool instead, but none of them are as powerful or as useful.)
Do you currently use and rely on software which you expect won't be useful to you in ten years time? I can't think of much personally.
(I do use IDA Pro, which has clearly adapted poorly to changing requirements - it still has scars of the 32-bit to 64-bit transition that get in the way of day-to-day usage. I hope there'll be something better in ten years. Of course, I could buy a cheaper, "higher quality" tool instead, but none of them are as powerful or as useful.)