WHY do we do this? To get replacement parts for some old men and women who have abused their own parts so badly but allow 'em to continue? I don't want to even consider the moral and legal aspects of this.

Then we start seeing if memories can be backed up and restored to new bodies, or if they can be run remotely like robots and... and it makes a GREAT comic story. But a rotten reality.

Also, let's not pretend we live in a bubble - if we don't explore this line of scientific research - it will not do ONE iota to stop other countries from doing so.  They will then reap all the treasury and rewards that are gleaned from such research and even IF they sell some of it to us, it will cost us immeasurably.

I have to say your "reasons" for not helping those who have "abused" their own parts rubbed me very much the wrong way.  There are exceeding few, if any, who are without sin when it comes to this.

You may not "like" it, but this is a toothpaste out of the tube type of thing. 

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Maybe. Or maybe to get replacement organs for anyone who needs them regardless of the reason. 

The abstract here may give some context as to why this kind of science may not be a bad idea (I do acknowledge that there may be ethical considerations here).

Same could be said for eating animals for our sustenance and pleasure. So if we ban xenotransplantation, we would have to ban everything. And we would be a morally better species. But we're not and probably never will be.