On the other hand, solar pv panels are quite close to their ultimate goal. The ultimate goal isn't being 100% efficient and converting all incident sunlight into electricity. But it is to be at grid parity. I was attempting to define the Sayed's Law for Solar PV industry when Jim Slattery brought to my attention the Moore's law equivalent for Solar PV industry.
Even though it can be debated whether the Moore's law equivalent is on track or not, but the reality is that the Solar PV industry is getting one step closer every day to achieving grid parity. Currently there are quite a few companies who are quite confident of reaching grid parity before 2012.