Link to the SourceWatch FAQ. 2-24-04
Telemarketing has become so insistently incessantly persistent because the pond is almost entirely fished dry. More and more people are registering their phone numbers on the national "Do Not Call" list designed to protect consumers from the solicitation calls.
Once a phone number is placed on the national Do-Not-Call list, callers are prohibited from making telephone solicitations to that number.
Only few suckers remain. A big portion of telemarketing has switched from 'outbound' (calling folks at their residence/business) to 'inbound' (what we think of as a call center).
There, in the latter, the same techniques employed in outbound soliciting are employed on inbound callers. They want a simple cancellation or adjustment and are subjected to insistent 'upsale' techniques ('wouldn't you really rather have THIS version?'). Because they truly desire/need help, they'll tolerate this up to a point.
But then they lose patience. This is bad for any business that wishes to retain clients. Since telemarketing/call centers lie at the center of the 'service economy', peddling mostly virtual artifacts like credit lines/insurance claims/et cetera, this does not currently bode well for this decade's economy.