What kilburn is referring to is that the business model that telco's use more or less stimulate this type of calls.

If a telemarketeer has to pay for setting up a call, rather than the end-user for accepting it (no matter how small the charge is), then placing millions of automated calls all over a sudden start costing money to the marketeer.

Think of it: the caller has the will to talk to someone - why should (at least in the past) this someone pay for that? The Euro-zone does it the other way round: you want to talk, you call, you pay.

Either way, in both situations with call volumes going down and people switching to data-type connections you see the price of calling/receiving calls drop sharply and as listed above the money telco's make comes from the data plans.