Problem is: I don't want to ship internationally by USPS or any other method to folks with low Feedback in "bad Countries". How eager are you to ship to someone with a 10 or 15 or 30 feedback rating In Russia, or Saudi Arabia, or Israel (one of the worst in my experience)? So I block every country. If I unblock countries in the global program so that buyers could have me do the shipping for less money, I open myself up to the low-lifes mentioned above and a decline in my seller rating if I cancel too many auctions won by the low-lifes.
The Global shipping program was supposed to be designed to solve the problems of late or no deliveries, dubious tracking, and the negative feedback and chargebacks associated with the process. I used to ship to England, Canada, Germany and France all the time with no problems, when I could require a US$ money order as payment in advance of the shipment. BayPal has ruined that with chargebacks at the drop of any faint complaint, and requirements for online tracking for the shipments not offered by most countries.
It's just not worth it anymore to ship internationally.