First, your assertion "college can be valuable but is not necessarily so"
makes no sense.You can always claim that "X can be valuable but is not necessarily so". Where X can be anything in this universe. Second, you are trying to turn a personal experience into a generalization. A good question to ask would be what would happen If the college enrollment dropped by 10% or 20% or 50% ? How would this affect the workforce and the industrial output? Another extremely important question is that how do you decide who exactly should drop out??
Should people drop out on basis of financial resources or some limited test of intelligence. The problem is that it is hard to tell who should enroll and who shouldn't. While certain subjects can be learnt online, a large number of subjects cannot be learnt. A university provides Labs, Wide range of subjects, access to a social network of like minded people, Faculty, Assessment and most importantly some guarantee of Academic Integrity. Universities are an example of the Theory of the firm.[1] You can surely separate different components of college education which I mentioned above, however there will be significant transaction costs. The underlying theme of this discussion is not about education or elitism. It is about allocation of capital.
Peter Thiel being a Venture Capitalist is interested in allocation of capital, thus the whole 20 under 20. Dont confuse his efforts with education or elitism. If anything his program might be more elitist than Harvard. [1] http://en.wikipedia.org/wiki/The_Nature_of_the_Firm |