I'll have to say that they have, but mainly because I'm not willing to pay full list price for a eBook as I might have been for a paper book.
I like to skim through books by new authors before buying them to see whether I like the style, so as this is not possible in eBooks, I tend to be more conservative in what I buy.
Now this goes out of the window when the Prices are low ($5 or less) or there is a massive sale
. Then I've found that I'm more willing to spend the money as if I don't like it, its not that big a deal.
The problem i've been running into is that a lot of the books I'll like to buy are not available as eBooks