A changing market place

Charlie Rice raises an important point when he mentions in one of his comments here that he is "forced to go to B&N as the smaller stores have closed." Matt talks glibly of a further 30% of sales online, but what's the tipping point? Can bookshops afford to lose another 30% of their dwindling sales?
Once the bookshops have gone, where's the market place for physical books? Buying online, is purchasing a physical book so very different to downloading an e-book - with its immediate delivery at a vastly reduced cost to the consumer? If (perhaps I should say when) the dedicated bookstores disappear, the industry producing physical books will collapse.  Will successful authors of the future be those best able to manoeuvre their way through the online jungle?  Will creativity be less important to the writer of the future than expertise in search engine optimisation?