A point-of-no-return in a career

I wrote about possibility of 'resetting options' after an MBA.

A discussion with a friend re-triggered my thinking on this topic. Is the decision we make in our MBA lead us to a point-of-no-return? Can you still laterally move into the industries that you eschewed in favor of others? Are the moves similar to those Vivek paul made limited to those in his category?

Will new industries like IT, BPO and the like be as accomodative as they have been till now? Will your choice be limited to such new industries?