^^ No thats actually pretty standard analogy. Since SONY was developing new platform with each successive release of its console.
ps2 - power vr gfx
ps3 - cell broad band engine
ps4 - cell broadband (rumored)
So that is the reason that SONY consoles have a life cycle of almost 8 years. Since when a new console would launch it would take nearly 2 years for the developers to get the hang of it. And as a result the best titles / true potential of the console will only be displayed once it has reached its half life ~ 4 years . It is also the perfect marketing strategy, and also one of the reasons that SONY consoles were so expensive. But i guess with the arrival of the cell broadband engine in the ps3 all that has changed. If rumors are to be believed then the ps4 will be based on the same architecture as the ps3. That gives developers a clear cut edge. Because studios like naughty dog have been able to maximise the cell broadband engine in the ps3 .By the time the ps4 releases the ps3 will be running at its peak. And if the ps4 has a cell broadband engine then they might as well start releasing blockbuster titles in 6 months .
Another thing which can be noted from this argument is that if SONY continue to use cell broadband engine then the launch price of the ps4 < ps3. And the cycle becomes ~ 4 years. Also this means that by the time ps5 launches in the market , cell broadband engine architecture will have to be changed. In essence what i am saying is that SONY is going to change the architecture ever 2 console cycles.
And as a conclusion which may be based on rumors i suggest you wait till the launch of the ps4 if you are not in a big hurry to play games. Else get a psp and keep your self happy.