When it's something people don't understand, then they value it based on how much they pay for it, period. Hell, it's amazing in fashion how much some of these things will go for. *picks up this month's Elle Canada* A single viscose-blend dress, by Donna Karan New York: $3,295. Pg 158 for those interested. Most people would say "It's a freaking, bloody black dress!!! What's so special?!?" Truth be told, people with little understanding of design are likely to like it more simply because it costs so much; "it must be better". (Personally, I could put something together that's respectably close from Sears. Yeesh. Not knocking the designer though, because it is a very nice dress, and probably custom-made too.)
The point is to reinforce the comment above about percieved and actual value. Few clients out there wanting photography done are knowledgeable about photography. That's probably why they're paying for a professional photog in the first place. So, they're probably not going to recognize the artistic subtleties in your port that make you a cut-above the rest, beyond when they compare your shots to blatently underexposed, terribly composed ones. So when they see similar ports, one from someone that's $600 a wedding, and one that's $2000 per wedding, they may very well jump for the latter, just because they may percieve they're getting more out of the deal.