Galahad pretty much summed it up. Making Space Invaders or Pong is a couple of hours work in any language. Making Monkey Island or Mario, you need a full time artist for a year, let alone programmers, music producers, testers etc. Making a 16 bit game of the quality people expect would need serious money behind it even if done not-for-profit.
If somebody opened a Kickstarter for an original Lucasarts/Adventuresoft style game on the Amiga I would happily put £50 in the pot, but it would require about 5,000 others to do the same! And there just aren't that many active Amiga users, only a couple of hundred left IMO (and by this I mean people who use their Amiga regularly, not the people who buy an A1200, get all excited and then sell it again 3 months later that every forum is full of.)