The reason that a lot of places are not doing this kind of polling is because these are done by polling land line phone numbers (if you call cell numbers you could get people anywhere in the world, if you call US landline numbers you get people who live in the US).

This method used to be perfectly okay when everyone had telephone service that comes through a wire, now that isn't the case. Because of this, there is inherent selection bias towards the kinds of people who would have land line phones (older people).