So what? Each generation is newer and better than the last. If you were looking at getting a 6xxx or 7xxx series CPU I wouldn't be as concerned. Again, you are talking about buying parts to get something FIVE generations old up and running. I wouldn't bother doing that.
I currently run a 3770K. I built this machine so many years ago I'm not sure when I built it. 5? 6? If the board broke and I needed to build something new, I wouldn't buy a board to get a CPU that old running. I would buy newer, so my machine can take advantage of the new things that have come up. For example, if my board broke, I would sell my 3770K, buy a 7700K and a board that supports that and reuse my DDR3 ram because ram costs so much. The crazy thing...