Possible if someone re-compiles the code to work on those platforms.

Very highly unlikely that it will happen due to the amount of effort that would be spent.

Even if this were done, the likelihood of those machines being used for WCG is very small. They were designed and purchased to make money. Running them takes energy which costs money.

Not that miners are not charitable, it's just that these machines are not the answer.

From what I know of bitcoin mining, most of the newer machines (less than a couple years old) are all ASIC miners, so by definition these are optimized for solving the math involved in bitcoin mining. Any dedicated integrated circuit almost certainly wouldn't be adaptable to WCG crunching. In fact, if I understand how these machines work, they actually can't do anything but bitcoin mining.

If you mean the older machines that were GPU based, you have pretty much the same problem. While they could be used for WCG - as we know from the previous cancer project, these too are fairly specialized rigs that aren't adaptable to the type of general purpose computing we do on WCG.

If WCG ever manages to deliver another GPU based project however, they might well be adaptable to that, but unless or until that happens, only CPU part of the hardware will usable for WCG. And since in most cases all of the performance of those machines comes from their GPUs rather than CPUs, I don't think most of them would provide much in terms of performance on WCG.