There is another simillar promise (again AGA only) for strategy folks that never got released.
Battle Isle 2 (check Amiga Format issue 59 - comming attractions)
For me turning point was move to USA (end of 95). When I got here there was no Amiga hardware or software in sale at all.
Also couple of PC games that just got released made me go PC route as the rest of the world.
When did PC outperform Amiga? When CD-rom has become standard on the PC. Amiga CD stillw as way more expensive and not suported by game makers.
Everyone new floppies were thing of the past... and amiga depended on them.