To add, Springfield is hardly the only source of a semi-auto version of an M14. There are many custom builders that can build an M14 much better than the Springfield shop. You would probably have to start with either a Springfield or an Armscorp receiver (there are a few others as well) but you could use all USGI parts and whatever stock (stronger than original and/or fiberglass) you wished, as well as whatever quality of barrel you want. The end price would not be tremendously different from that of a Springfield for the higher models. I can give recommendations for custom M14 builders.
The reason the M14 is not sold through the CMP is that the ATF sees it as a machine gun. Even if the receiver has been altered to prevent full-auto parts to be installed, the S/N of the rifle is attached to a full-auto version and the ATF will not authorize regular sales. IE, thousands of M14s have been cut in half and trashed.
The CMP doesn't sell M16s for the same reason, however, they HAVE sold AR-15s which are the civilian equivalent, semi-auto versions. I don't know if they will start this program again, but I understand that it was a big sucess when they were running it.