I think there will be growing pains as local dealers adjust to the new environment. However, the internet is making high-end audio known to an ever-widening number of people which can only be a good thing in the long run. I also think it may force companies to offer more value for the money as it is easy for people to share information about high value equipment and low quality equipment as well.
Personally, I'm thankful for the internet. With the price of good stereo equipment, I would have had a difficult time affording my modest system. Online, I picked up what would have cost around $4700 new for around $1400, mostly used. Besides a CD player and turntable for me, I needed a tuner, DVD player, and remote for my wife to justify the expense. Add the fact that it all sits in a big room with tall ceilings and you can see that putting together something at a local dealer would be difficult at best, especially considering that there are no decent used dealers where I live.
My choice, and I do not think my situation is unique or at all rare, was not buying online or buying locally, it was buying online or not buying at all for several years.