Whatever happened to those 10-10-987 type phone numbers and their commercials?

They still exist. You can still call using 10-10-987. Here is their web site: http://www.1010987.com/

But most of the dial-around phone companies have seriously jacked up their prices and some have even added monthly fees. The problem for them was that they depended on your local phone company to do the billing for their services (the charge for your 10-10 calls generally appear on your local phone bill). Local phone companies have increased the billing fees they charge long distance companies so much that they can no longer afford to charge cheap rates.

The dial-around industry had its best days between when AT&T lost its monopoly on long distance phone service and the time when local phone companies were again allowed to sell long distance service. Before people could buy long distance service from their local phone company, consumers were forced to shop for long distance phone service and compare prices. Now most people just sign up with their local phone company for whatever service they offer, often accepting local/long distance combo packages that end up costing them more money than if they shopped separately for the services. And then the cellular phone industry rose to prominence. Almost all cell phone plans today include long distance at no extra charge, which again is a disincentive to consumers to concern themselves with long distance rates.

Finally. landline telephony is overall a declining business. People are dumping their traditional phones for wireless or VOIP. The economics are no longer there to mass market the product.