I see some of your point.. though I think the series issue might be part public preference and part that there is a known audience for the works. If book 1 sells X, its probably a safe bet that book2 might well sell at least .8 or .9 X.
That being said, there are still authors who haven't gotten too much sequelitis. I mean almost any author, particularly a science fiction author can be tempted by following up ideas and plot lines that were undeveloped in the original story, but some authors seem pretty good about limiting themselves to no sequels or just a few.
Another thought... another problem with ereading from a publisher perspective is that its much harder to do book signings... you probably are not going to try and get your Kindle or Ipod Touch signed like you would a hardback
. So some sorts of promotion are going to have to change. I think Baen's web subscriptions might be an idea for a lot of publishers. A return of literary magazines perhaps? They can concentrate on newer authors, and pay them to write short stories and longer works with the longer works being broken up serial style and released over a certain number of issues (The way some of the sci-fi Magazines still do it). It will allow a way for newer authors to develop a market before they try to sell novels as stand alones.
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Bill