Obviously, however, replacement cost for intangibles is impossible to estimate accurately. Especially if you consider the risk that the "replacement" is a failure or doesn't accurately replace the institutional knowledge, intellectual property and goodwill the company has accrued.

It is fair to say that stock prices are not representative of current value, but rather the long term value and growth the company has yet to realize. So in that sense, Tobin is right, but the growth the company has yet to realize is really just goodwill accrued as an asset. Meh. I'm rambling now.