I wonder if your hiring process isn't more narrow and exclusionary of independent learners than you think. It is really quite easy in 2013 to have racked up 8 years of real high-quality development experience without having any idea how memory allocation works at a detailed level. For some portion of the people with 8 years experience it will be easy for them to go and independently figure out how it works and for others it won't. You want people in the first group, but you can't find them just by asking them questions about memory allocation.

(Also, do you do something having to do specifically with memory allocation or is it just your pet entry on the list of things you think everybody should know about to not be dumb?)