Scott,
As a big proponent of preamps, I of course agree with you. :) There is no question that a highly optimized commercial use radio is probably as good as it gets with respect to front end NF and gain at the antenna connector. However, that describes virtually NO rig used by typical amateurs. Even purpose-built rigs like the FT-847, IC-970, TS-2000, etc, have significant tradeoffs not necessary in more expensive and focused commercial use equipment.
And for every one of these rigs, how many people are operating with equipment which was not designed with satellite ops in mind? For instance an HT is designed for a strong signal environment, and the specs show that. It is well designed for its purpose, which is not the way we use them on AO-51, etc. Or an FT-817, FT-897, or similar which many use as part of their station?
And of course, putting that quality preamp at the mast, ahead of all the cable losses, is a whole other issue. Even a mediocre preamp will help a mediocre radio, but fortunately there are some decent preamps these days which compensate nicely for the tradeoffs and limitations.
73s,
Alan WA4SCA