No, in the States ethernet rules. You often see a dual USB/Ethernet modem, but a solely USB modem is rare.
Your choice of routers as a result is much wider. I honestly mistrust USB for connectivity, and the December 2002 USB Standard Committee decision to relable USB 1.1 as now "USB 2.0", and 2.x as "2.0 High-Speed" adds confusion to the issue.