technically, it's demand that is meant here by what's elastic (or not). there's also a price elasticity of supply (eg, if tuition goes too low, some colleges will close).

the way the GP used the term was understandable to me, and how I'm used to seeing it used. it's basically shorthand for 'people's [demand for college degrees] became price-inelastic'. if you want to use it differently in your communication, it's up to you. just remember that people might understand something other than what you meant.