I see where you are coming from, but it also looks to me that you are ignoring the 'supply side' of that argument.
Take your Doctor example - it is not just that we value medicine, or our bodies. The supply side issue is that it takes a lot of smarts, dedication, time and money in school to become a Doctor. A relatively small % of the population is capable and motivated and interested enough in that line of work to pursue it. It takes a reasonably high compensation to get enough supply.
Some will argue that there are some non-free-market issues at work in Doctor supply. That may be true, and if so should be corrected IMO, but it is part of the current supply equation and it does explain why Doctors receive the compensation they do (which, all things considered, does not strike me as unreasonable anyhow).
Sea Shells versus Gold - supply issue again.
I'll counter that with a Renoir painting - just a couple bucks of canvas and oil paint, but we value it much higher than that. There's lots of canvas and oil paint, but very few Renoirs.
Another example - we all 'value' air, but because there is usually a good supply of it, we don't pay for it. If it is limited in supply (deep sea diving?), then we are willing to pay. Only difference is the supply, not the intrinsic value we place upon it.
-ERD50