I have two major problems with e-books. The first is the minuscule size allowed by the e-readers. I had to fight to get my first edition into the file space permitted. My second edition at 385 megabytes doesn't stand a snowflake's chance of getting into an e-reader as the average user, even if that file size was permitted, wouldn't want to wait for it to download. On a 3G download that would take at 600kbps (most 3G works at this speed) 5,256 seconds or about 87 minutes. That's not feasible. Similarly on a shared wifi network where the user is likely to be getting just 1.4mbps, it would still take 34 minutes. The second is the fact that e-readers are not widespread enough to be worthwhile.
What do most people use their tablet computers for? They use them for casual web browsing, playing with Facebook and other online games. There is no reading done not any serious work. Lacking a keyboard, nobody wants to use a tablet computer seriously. Speaking from personal experience, I had a color tablet. It was OK until I breathed on it and then the screen went bananas. That was a total waste of time. I never read a single book on it - not because I didn't have a book but because I didn't like reading off a glowing screen. It was not relaxing. I spent 90% of my time messing about with websites etc - most of which wouldn't work well without a desktop anyway. So, I sold the blasted thing. Tablets are not serious devices, they're for people with money to throw around to play with. They're adult toys though most adults would not have the guts to admit that. It's a bit like smartphones. They're just toys too. I have one and I admit I spend most of my time playing with it when I'm not working.
What about black & white e readers? They're much easier to read though the text is far from black and the background is far from white or even page color. It's like reading darker grey on lighter grey. Then there's that horrible and distracting flicker every time the page has to turn. It's all very unsatisfactory and very unnatural.
I see the array of ebooks online and ereaders just seem to have allowed people to churn out ebooks of minuscule lengths and minimal quality for maximum prices. I have had the opportunity through work to see some of them and have not been favorably impressed. It is unsurprising that amidst this sea of trash that my ebook can't even be found. At least with Amazon, the print editions can be found and purchased. I do not see the situation as improving. There is zero editorial control of ebooks for quality, content or length.