I don't know much about why there are such restrictions, do they charge different amounts in different countries? Shouldn't it all be pretty much the same, money-wise? Is it an issue of censorship based on the particular country's politics?
It's all about the licenses. Most of the time a TV station with deep pockets buys the rights for a region for a given timeframe from the producers. And they wouldn't be too happy if you could binge watch a whole season on Netflix before they had time to show all the episodes on TV.
So unless Netflix outbids every TV station for the content rights all the time they will always have somebody crying for regional blocks.