[ckz]

As with most artifacts, survivorship bias will ultimately dominate.

Some code will prove itself to be unusually durable (parallel: the pyramids) or some will prove to be so useful that someone will maintain it (roads that have been used for 2,000 years).

Most does ultimately fade to time.

That said, I use code daily that folks wrote 20+ years ago. Not just continuous lineages like an OS kernel, but actual applications written decades ago and never updated since.

Likewise, while most web sites/applications I've built for clients probably only exist on a tape in a datacenter now, people still upload videos of games I created 15 years ago to Youtube.

Getting code to last is all a mix of innate durability, utility to others, and some luck. :)