I agree that this sounds good.

But I still don't know why they have to be two different units. I understand Europeans have a single unit.

At the very least, even side-by-side they could make a flip-thingy to get the cloths from one to the other.

Can you imagine unloading your dishwasher to load your clean dishes into a dish dryer?

This is a good idea. Units that wash and dry in the same drum are common. You can find dozens of models on-line. However, having a unit that uses separate sections for washing and drying would have the advantage that you could start washing a second load while your first load is drying. This would save a lot of time, especially for large families. Of course, it would have to wait until you remove the first load from the drier before it could dump the second load into the drier.