The 80s and 90s PC games still unbelievably being updated today

Pffft that's nothing, people are still making new games for the Atari 8-bit computers and the 2600 and even selling them on cartridges. https://atariage.com/store/ (also more sold on the forums not carried by the store).

There's even a Halo 2600 for the Atari 2600 made by Ed Fries that "once worked as the VP of Game Publishing for Microsoft's Xbox division and was instrumental in bringing Bungie Studios into the Microsoft studio family" https://atariage.com/store/index.php?l=product_detail&p=998