I'm currently working on some Amiga projects for my own amusement. For me, a lot of it is a feeling of unfinished business. I grew up with the Amiga and wanted to be a part of that scene but I didn't have the money for books and development tools.
I also prefer old style game development as opposed to using frameworks like Unity or Unreal engine. It's a different feeling when you have complete control of the entire machine and everything you need is in one or two reference manuals. It's a more focussed and immersive experience. You can really get in the zone. Also, It's a lot easier to do acceptable artwork, especially for an 8bit machine, and with modern tools you can do things that couldn't be done back in the day.
Also, I've been involved in indie development for modern platforms and made about as much money as I would have releasing an Amiga game in 2021 :) So now, I figure I will just please myself and work on platforms I enjoy.