The money spent by corporations for telemarketing will be shifted into other types of marketing- like radio or tv ads, billboards, direct-mail campaigns etc. The money won't just disappear into the aether.
No need to hire people for that. No new redio jocks will be hired to read ads. No reason to think more ads will be made, they will just be played more often. Direct mail is highly automated. The machines will run a little longer, that's all. True the money won't just disappear, but a lot of businesses whose products are best suited to telemarketing (there is crap, but there also are excellent products that don't sell well with other means) will definitely suffer. I sold a lot of high quality products in direct sales where telemarketing played a key role in getting appointments, and a very large percentage of the higly satisfied customers all said the same thing at the beginning. They said 'I don't want it,' 'I'm not interested,' and 'don't call me again.'
For myself, I do insurance now. It's exempted. What's your number fool?