I see three main factors in the decision for limiting editions: marketing, logistical, and financial. The fact that one can produce practically unlimited number of identical prints with today's technology is irrelevant: limiting editions is an accepted practice, and even desired or required in some circles as pointed out in the article.
Because when I look at the photographers in the same nature/scenic space whom I think are the most demonstrably successful at selling prints, such Peter Lik (of course), Tom Mangelsen, Ken Duncan, Rodney Lough, they *all* limit their editions.
Although it's hard to say which photographers truly are
financially successful since anyone can make a very professional-looking website for a modest investment, majority of the ones that are most well-known outside of photographer-circles do indeed limit and number their editions.
Since Alain claims that it is mostly a
marketing decision - and I agree - it would follow that limiting editions is a
prudent marketing decision given the evidence. I'm sure it's not the most important one, but there seems to be strong correlation with limiting editions and superstar success.
Logistically John Camp's view makes most sense: sell all you can when you have fewer customers, and limit editions when you would need to hire (too many) assistants to serve the needs of a growing clientele and/or would need to cheapen quality.
I wouldn't know how well printing volume scales, but my understanding from reading several of Alain's articles and elsewhere it's clear that keeping top notch quality in printing, matting, packing and mailing can become a full-time job very quickly. In these cases artificially limiting editions makes perfect sense from the logistical point-of-view alone. Tiered pricing as proposed by Alain could also be a solution.
Financially limiting editions is for those who have a small market segment or niche. If you have only a limited number of buyers, you have to make your margins from fewer units. Artificial scarcity allows one to ask for higher prices. I'm sure that fine art buying customers are relatively affluent, so they can also afford to pay higher prices - so asking for "too little" money from them would leave money on the table. And limited editions themselves as a marketing tool can attract such a crowd.
For those who sell whatever is in vogue and a much larger and/or unsophisticated market (saccharine HDR, kittens in ballerina dresses and pugs playing cards, etc.), the decision to limit or not limit editions is probably more about marketing and logistical points discussed above.
Finally, limiting editions doesn't make sense for the star(t/v)ing artist. For the vast majority of artists obscurity is the greatest threat, especially in these days of commodized photography and low barriers to entry to even high-quality output. Of course, and as Alain argued, one can create limited editions so large that they will never be met.