Hip replacements don't fail because the immune system kills them, though. They're worse at wear and tear than original bones.

This is simply not true. My grandfather's implant, for example, was in splendid shape... but the bone around it had impacted and eroded so fiercely that one leg was 3/4" shorter than the other.

Pacemakers have to be swapped because battery. Nothing to do with their compatibility. For pacemakers, the original leads might stay in forever.

This is also simply not true - you're speaking to someone who spent a year designing and testing implantable shock/pace leads for atrial defibrillators. The implantation helices lose conductivity due to plaque build-up and the conduction coils wear mechanically. Again, our design life was ten years. I built the testers to simulate ten years of normal wear on implantable shock/pace leads. And I broke them.

Yeah, but I'm saying that progress is inevitable, and if we can have a 256-pixel grid, we can get up to and beyond original eyesight.

Yeah, but I'm saying you're wrong. The progress you're looking for is on the body side, not on the gadget side, and in case you hadn't noticed, that side is not progressive.

Nothing to do with wishing, it already works. Example.