> A truck and a tank have a lot in common

Maybe in 1942. Modern tanks cannot be built on highly specialized production lines that build road vehicles without years-long re-tooling. M1 Abrams tanks don't even use piston engines, they have turbines.

A older, but well documented example how specialized modern automotive production has become is the Mercedes Benz 500e. In the 90s Mercedes wanted to build a more powerful, wider version of the E class. They added 56 mm to the front fenders and discovered it wouldn't fit through the production line properly. MB contracted for Porsche to handle the low-volume 500e on a different production line.

> This is the same reason the Navy has for building ships in the US even though they can be done other places cheaper.

You'd think the biggest war machine on the planet would benefit from economies of scale by now. If they want to stay sharp they could build commercial ships between the ocassional war ship.

If you don't believe in the power and corruption of the military procurement industry and the military itself, then your comment is so unrealistic as to be deluded.

If you do believe in it, then it's simply irrelevant. Given the other reasons that the US military is spent with profligacy on US manufactured goods, maintaining 'truck know-how' does not register. If the know how consideration did not exist the money would still be spent in exactly the same way.