I agree with the OP. Selling a high-end assembly-line pistol with just one magazine is, in my opinion, short-changing the customer. I passed on Kimber about ten years ago, and bought a Springfield Armory micro-compact instead, partly because Kimber only provided one mag.
The prices were roughly the same, around $900, the quality looked good on both guns, but the fact that the Kimber only came with one mag stuck in my craw a little. So I bought the SA loaded, and have been very happy with it, and both the mags that came with it.
I bought a new Colt Series 70 gov't. model in 1973 that only came with one mag, and I was happy with that. Still have the Colt, with the original mag, and both still work fine. But times have changed, and I like the idea of getting two mags with a new pistol. It just seems "natural" to me.