The MSRP, if something even exists for such price elastic items as VGA cards, is probably still about $299 and $399 for the 5850 and 5870. Initial reviews for those cards had street prices around $20-30 below those prices (Anandtech listed as $379 and $259), probably accounting for the typical discounting expected. It wasn't until output and supplies undercut demand that we actually saw prices spiking above the base line $299/$399 prices.
Naturally, they can't stay static for too long (they are VGA cards), but it just might take longer than usual before we start to see the normal heavy discounts and deals, or we see ATI drop prices on those cards to vendors.
But it's already been about 5 months since they debuted which is an almost unprecedented length of time before seeing such discounts.