Sony and Microsoft cannot just drop the prices of these consoles indefinitely. Particularly in the case of Sony, you can't just keep lopping hundreds of dollars off at a time. Sony and Microsoft have lost billions -- literally billions -- of dollars already trying to get these things into people's homes. There is a limit. This is about money. It has to end.
I think many people in here simply disassociate marketshare and gaming completely from economic realities. For example, for many people, the reason they prefer the PS3 and 360 in the first place was that they were more powerful systems, and that is the exact reason why they cost so much money. If the PS3 and 360 launched at lower prices, they would have also been much less powerful systems. In which case you probably wouldn't have liked them in the first place.
As a person who frequents a great deal of technically oriented forums, this isn't a malady particular to gaming afficianados. Whatever the cutting edge of technology is in any market sector, there is a small, technophile group that insists that if [insert high tech device here] was 100 dollars, it would be outselling [insert low tech device here]. Which is true, of course, but the reason it costs so much more is because it's so high tech.
And when the product in question finally reaches that 100 dollar level, it's no longer high tech anymore. It's now the low tech product. Something new has been created that costs a ton of money, and now the technophile crowd is insisting that the new product would be outselling the now-old product if it was 100 dollars, too.
The conversation is completely disassociated from economics and reality.