As a former student if I were faced with the choice of purchasing a dead tree version that I could resell or an electronic version I couldn't then the electronic version had better be less than the dead tree minus the resell value. If it's not then I'd buy the dead tree version.
What will happen is that the electronic versions will be cracked and widely disseminated. The publishers will lose out on even more revenue and withdraw the electronic editions.
Pessimistic, no. Realistic, yes.