It's a shame Zilog stopped making Z80s. Presumably this means you can't make one of these from new components any more. Perhaps someone could create a new iteration of the same idea.

The Z80 instruction set lives on via the eZ80, Z180 and others which are binary compatible with the original Z80 instruction set. Unfortunately Zilog stopped making the 40 pin DIP package a couple years ago so yeah this specific board will be hard to source. You can still find them on gray market, mostly ones that have been desoldered from existing boards.

Even if you made a version of this board with the footprint changed to the QFP eZ80, it probably wouldn't work because the eZ80 has different memory mapping and clocking differences.

You can probably put together something similar with A-Z80 [0] or a similar FPGA redesign.

[0] https://github.com/gdevic/A-Z80

Luckily so many were made, they will be around for a while yet. For years now you've been able to buy (recycled?) ones on Ebay or Aliexpress, and at a price much cheaper than the new ones sold for.

It will probably be a decade or longer until those sources start to dry up, but even at that the Z80 will never become as rare as say, a SID chip.

The Z80 is still used in consumer products. TI-80/TI-83 calculators are a well known example.