If one has a low cost back end that can do the translations, do the legal matching work, set up the conditions tables for these things to work seamlessly for different regions while reflecting the options, choices and legalities of the different region, you got a pan-nation service.

Its not impossible, its a matter of matching the possible returns with the costs of carrying out all the customization. Simple terms - ROI - Return on Investment.

Usually for the startups, it could result in better ROI if they invest available funds to increase capabilities and increase survivability in the home market (especially when it is as large as the US and a field as dynamic as the net/IT) than to spend that money on customization of the same services/capabilities in foreign/small markets. Otherwise, one risks losing the home market itself. There's is something from Sun Tzu on that I guess, about securing your home first.

Of course, once the size, sustainability and cash flows grow, then the picture and priorities can change.