I think people expect a lot more from an Amiga game than they do from a Spectrum game, so they take a lot more effort to make. I also think the 8bit scene appreciates the games they get far more than the Amiga scene, since nearly any game that does come out for the Amiga is ignored or overlooked by the majority of the community. They may play the game, but very few people give feedback and the makers of these games lose motivation to work on them anymore.
The conclusion I came to long ago was this: If no one out there is making Amiga games, then I'll just have to make them myself!
Learn to code, pixel, compose, design or write and team up with someone else motivated enough to make new games, it can be a lot of fun and it's really rewarding to see people enjoying your creations.