Updated from 10:55 a.m. EST Apple ( AAPL) is a strong swimmer, but it's fighting two nasty currents: a plunging economy and a strong netbook undertow.With U.S. unemployment now at 8.1% , it's hard to imagine consumers rushing out to buy new computers. And increasingly, when they do, they are opting for $300 stripped-down models called netbooks from Asian manufacturers like Asus and Acer. This trend isn't working in Apple's favor. With no populist urge to go downmarket with a netbook of its own, Apple is left proudly pedaling a line of luxury computers to ever-more cost-cautious crowd. Investors are getting the drift. Apple shares were down 5.9% Friday amid a minor tech rebound. The average price of a PC is about $720. The average price of a Mac is nearly twice that at $1,408, according to Technology Business Review. To be sure, some Apple watchers argue that Mac prices are competitive with similarly-configured all-in-one PCs, but the overall price picture shows a glaring contrast between Apple and the rest of the PC market. Citing a "deepening global downturn," JPMorgan analyst Mark Moskowitz cut his Apple estimates for March and beyond in a research note Friday. Unlike PC giants Dell ( DELL) and Hewlett-Packard ( HPQ), which rely more heavily on business customers than consumers, about 75% of Apple's fortunes are tied to consumers. That market is under some pressure, Moskowitz points out. "In prior recessions, the consumer had been fairly resilient, but mounting job losses, shrinking home values, and tight credit stand to make the current recession quite more challenging," writes Moskowitz.