Well certainly the internet will hurt anyone's business if it is dependent on consumer ignorance, since the web is such a good medium for information - not just passively, but interactively too (that's why audiogon is so great ;).
Frankly, I don't know what I would do if I were a highend retailer to make the best of it. imho opinion I MIGHT go with Rimbaud: il faut etre le plus moderne possible (you must be as modern as possible). In short: Leverage the new -- infant -- medium of the web as much as you can - try to turn the disadvantages of the web to your advantage. For ex.:
1. Have a highly interoperable, well-designed website w/ good web copy (no typo's, high quality compressed pics, fast-loading, search-machine optimized text, imho no frames [I want to set a bookmark on my apple's eye, right?]).
2. Put teasers on high-volume virtual markets (ebay etc), but also specialist/niche used markets (audiogon of course and others) to draw attention to your existence.
3. Help the consumer (provide quality information/advice) to help you ($$pend to buy your stuff). Small example: post (links to) favourable reviews/interviews/etc. of your wares, if these are offline (esp. often for vintage high end), get permission to put a reprint on your site.
4. A clichee goes: act local, think global. It's not entirely wrong - wrt the latter, there are many europeans, asians etc. w/ deep pockets who wd love to spend their money on highend audio. But what about power supply issues, customs, shipping? Insofar possible, address these issues clearly, offer to ship overseas w/ the correct PSUs, etc., make S&H rates fair and transparent, etc.
5. Educate your clients, help them get involved in, develop a taste for your stuff - you can't lust after that of which you are completely ignorant (for instance don't just assume that everyone knows what all those acronyms mean).
6. Resolve to stick it out for the long-term and keep on your toes, keeping abreast of changes in fashion, tech, etc., but don't follow these slavishly. Develop your niche, take pride in what you sell and show backbone (everyone respects that).
...
Sheesh, anyone who just took some of these things for starters and got them right must really know what they're doing, and genuinely care. That's where SOME (maybe enough, perhaps lots) of the money wd go.
OTOH, one might just assume that a retailer ignoring all these kinds of things, either doesn't really care too much, or just isn't savvy.
Having great products helps of course. But it would be foolhardy to believe that that is either a guarantee of success or even a safe hedge on getting "killed" by the internet.
I'm aware I cd be way off base. It depends on what you mean by "highend". If it's out-of-sight highend, maybe the best strategy is to just ignore the web, except for posting minimal contact info. No one who has serious money to spend wants others to have the same thing. Here, the real currency may be just word-of-mouth. just my 2 cents worth.