You would in any case have to write it in ASM. This means a complete rewrite of all C++ code. Just that would be a very time consuming task and thus very costly, either monetary or the free time by unpaid programmers.
One reason the Amiga died as a commercial computer was piracy. The guys behind Pinball Illussions said it would be their last game because 75.000 expected sells would just break even. Everybody loved that game, but most gamers didn't pay for it.
Remember, the game came on a few disks but still needed to sell 75.000 copies to just break even. That says a lot about the amount of work going into game development, especially when programming in ASM. Today we have a lot of helpful tools that makes ports to different platforms easier and also gives programmers a lot of shortcuts. But not with ASM. It's as daunting as ever.
Do not underestimate the workload for such a project.
