Not entirely true-- there's a big difference in pricing, and margins.
A basic figure costs $8 and sells for less than that-- I've been asked not to say how much, but the margins aren't and never were great on Kenner or Hasbro action figures. (Particularly if Wal-Mart is in a price war mood.)
Meanwhile, an SDCC figure gets to sell for $14. Even when you factor in the Star Case and retail space (booth), it's still a huge, huge markup for Hasbro over what Target would pay for a regular figure, plus Hasbro gets 100% of that. Even if all Hasbro nets per SDCC Zarana is $8 of that $14, that's still significantly better than what they make off an $8 Steel Brigade figure at the Toys R Us or your favorite online toy shop. They also don't necessarily have to deal with as many distribution steps-- depending on their supply chain, it can go straight from the factory to the boat to SDCC, rather than having to make stops off in Hasbro's distribution centers or the DCs of various retail giants.
I don't know Hasbro's quantities on an SDCC release vs. normal basic Joes these days, but I do know SDCC items get significantly better margins, cost more to the consumer, and actually GET marketing support because every blog under the sun will report on them. You might see MTV or CNN mention an SDCC figure, they'll never mention the regular stuff, it's a great way to make something for collectors that stands a chance of succeeding due to the hype and the heat from the show.
Add to the mix retro packaging and a figure sculpted in the 25th Anniversary "classic" style AND the fact that the main line includes NO female figures right now, and this is probably Hasbro trying to cover their butts by putting this particular figure out in the safest possible environment to guarantee a speedy sell-through.
Seeing how Low-Light was very 1980s-ey in his look, they could probably stick in more "classic" figures and do just fine, and I'd be genuinely curious to see how a female figure would sell through in Joe these days. Obviously, Hasbro isn't as curious, so at least we got A Zarana which will probably get cheaper and cheaper on eBay as time goes on rather than no Zarana at all.