@pixelpaperyarn (tl;dr I've run an ebook publishing company for years and love the format + availability of ebooks)
I've bought and published ebooks for years -- for me it's all about cost, especially in the academic world. I can publish an ebook for $3-4, when to sell one in print form would be at *least* $10 through something like Amazon's print-on-demand, without much revenue back to me at all after Amazon's cut.