https://en.wikipedia.org/wiki/A_Canticle_for_Leibowitz

I have a Displate of a 555 in my little maker corner someone gifted me once: https://eikehein.com/assets/images/makercorner.jpg

His response still resonates with me today: a military grade 555 would work in extreme conditions (e.g. heat), would last pretty much forever, would consume virtually no power, and will still cost you a penny.

Sometimes that's exactly what you need. Reliability, durability and cost trumps the power of programmability.

Really it's such a useful almost universal lego block of a component that it's hard to imagine it going away anytime soon. Sure microcontrollers are as cheap as chips these days, but you get a lot more with them. Do I need to say that sometimes more is less? Can think of scenarios where you absolutely don't want to see a chip containing firmware/code which needs auditing and locking down.

A modern CMOS microcontroller has a much more limited lifetime. Depending on model, you can hope for 10 years or 20 years, but not much more than that because very small MOS transistors and flash memory cells eventually die, unlike the more robust bipolar ICs (whose active regions are buried in the semiconductor crystal, not located at its surface, like in MOS devices).

1: https://www.youtube.com/@hcamen