ReadWriteWeb got their hands on a statement from Sony, and that's certainly one way to interpret it:
"Pricing is one consideration in the dedicated reading device marketplace, but Sony won't sacrifice the quality and design we're bringing book lovers to lay claim to the cheapest eReader," said Phil Lubell, VP of Digital Reading at Sony Electronics. "Our global customers expect to get the best digital book reading experience and we're concentrated on delivering that by investing in Sony's award-winning design and original digital reading enhancements, such as eBook library borrowing and the only full touch screen on the market."
They won't leave the market entirely, but I could see Sony giving up in the US. Then again, once they abandon the US market, what will they have left?
P.S. I'm waiting to hear from my contact at Sony. If I find more info I will post again.