Here in Australia Huawei and ZTE modems seem to be the only thing available from the majority of providers. Certainly the three major carriers have them (or did six months ago when I last looked), and I haven't seen a non-Huawei or ZTE modem from any of the MVNO.

Perhaps because in the USA you have different frequency bands?

Argh I can't believe I made that mistake, I even know it is wrong!