Yes, to some extent.
The benefit of replacing organs with artificial ones is that humans become like cars, and medicine becomes like car repair. When something breaks, you find the broken part and replace it. Currently, people die from organ failure. That wouldn't happen. Liver cirrhosis: wouldn't happen. Early-stage pancreatic cancer: wouldn't happen. Type 1 diabetes, most heart conditions, ruptured organs, emphysema, arthritis and blindness would all be curable if we had the option to replace damaged or defective organs. You could replace entire bones at a time to reduce the effects of osteoporosis.
However, it wouldn't make us immune to everything. I'm drawing the line here at the brain, since replacing the brain but preserving your consciousness and memories is far beyond the technology we're discussing here. 10 percent of Americans over 65 are afflicted with Alzheimer's disease, which affects the brain. 335
Alzheimer's is the 6th leading cause of death in the US. It wouldn't be solved at all by this new form of medicine.
There's also the matter of cellular senescence. When cells divide, small amounts of their DNA are lost. This results in the cellular DNA shortening slightly with every division. To protect against adverse effects from this, the ends of your chromosomes are tipped with sections of random DNA called telomeres. This provides a buffer of DNA that can be safely deleted without damaging your genes. However, as you age, the telomere shortens, and eventually, the functional DNA in your cells is damaged, causing the cell to stop working and just sit around doing nothing, taking up energy. The more of these 'senescent' cells you have, the less efficient your body is, and the more likely you are to develop chronic problems. Replacing individual organs would only help with this to some extent, since we are more than just a collection of parts: every cell has its own complexities.
Of course, metastatic cancer would be completely unaffected by this treatment.
So while organ replacement would make several life-threatening ailments trivial matters, it wouldn't address other, equally deadly problems. Statistically, this would increase life expectancy by a decade or two, maybe, but it wouldn't halt aging or remove the medical problems associated with it. 335