It is important (although I would not belittle individual cells or "simple organs" (depending on what that might be?). Cell transplants have saved a lot of lives (in the blood / bone marrow area) and people keep dying today because there aren't enough of these cells to go around.
If there is such a thing as a simple organ, a priori it might seem like a good stepping stone on the path towards a more complicated organ, no? So I think you've answered you own question. Start with whatever you find is simple and still valuable... Then apply the lessons learned and the money made (if any) towards more complicated things. Good rule in life in general ;-P
The most high profile effort towards the organs you mention is probably the Rothblatt / Venter alliance, to grow them in pigs.
How you personally can make it go faster, I'm not sure. Figure out how to make them, and then make them