You are assuming two things. That the need for pharmacists will continue to decrease as time goes on, and that thousands of walgreens will actually meet these needs.
what i am assuming is this:
if u need a walgreens to open up to get a job, that is not a good business model for a prospective pharmacist.
i replied to the post that said by 2010 there will be 7000 new walgreens opening up. another poster said 1500. for arguments sake, let's say 15 000 by year 2014. for the point i'm making, the numbers themselves don't specifically matter (we can't agree on them anyways).
at some point, those 15 000 walgreens will be filled. let's say in the next 10 years, from 2007-2017, pharmacy schools produce enough graduates to fill those stores. it will happen, its just a matter of time. (i don't want to go into the reasoning here). at some point, supply and demand equilibrates. for the beginning, pharmacist supply will be lacking, so demand goes up, and salaries go up.
but the problem is, after 2017, when all those 2007-2017 grads have jobs and are happy, in 2018, there will be new grads. in fact, for the same period, from 2018-2028, there will be another 15 000 grads coming out, with no personal walgreens waiting for them.
as such, supply will become plentiful. a 2018 grad who is unable to find work elsewhere, will be happy to work for half the salary that walgreens is paying u. in 2019, yet another grad is willing to work, at a third of the salary. walgreens will be in a position to pick and choose.
anyways - the point here, isn't even about walgreens.
if schools are producing enough grads to fill a rapid private commercial expansion, unless they concomitantly reduce the number of grads they produce when that commercial expansion stops, there will be an over-abundance of grads at some point. over-supply will lead to decreased demand, and decreasing salaries.