The harsh reality is that a “migration toolkit” only helps the developer build an additional platform-dependent version that presumably has to be maintained, updated, and tested for the lifetime of the product. For all those costs to be worth it, you have to think you will add a significant number of players.
If I’m developing a PC game, I would give investing in producing additional versions for Xbox and PlayStation SERIOUS consideration because of the large numbers of established players. The additional costs are likely to be worth it. I just don’t see the additional costs for a Mac version panning out.