Looking into this a little bit more: it seems that there are actually some Z80 (actual Z80, not Z180, etc.) chips that will remain active. For example, the Z840

Looking into this a little bit more: it seems that there are actually some Z80 (actual Z80, not Z180, etc.) chips that will remain active. For example, the Z8401510FEG chip is not listed on the end of life notification, and is still listed as "active" at Digikey. https://www.digikey.com/en/products/detail/zilog/Z8401510FEG/929034 https://www.digikey.com/en/products/detail/zilog/Z8401510FEG... Now the thing is, this chip is a different package than what most people probably expect when they think "Z80" chips. It's QFP, not DIP. So not a "drop in replacement" for many situations. But you can probably use a QFP to DIP adapter or breakout board and use these in many places you'd want a traditional Z80. And if you're designing your own ad-hoc retrocomputer around a Z80, this should work fine, albeit with the constraint that you have to work with QFP chips.