Just a few years ago, we would never have suspected that in the middle of 2008, we’d still be trying to figure out how bundled telecom services work.

For AT&T and Verizon, which have their own in-house mobile and video offerings, quad-play service models aren’t so mysterious, and the term “wireless substitution” is just as innocuous as it sounds -- customers may as well switch out their voice service for mobile. (In fact, AT&T may have hastened its own wireless-substitution effect recently with all-you-can-eat plans, and as a result, it reported a surge of new additions to its broadband subscriber base this year thanks to a double-play bundle of standalone DSL and mobile voice.) But for just about anyone else, the business cases underlying bundles, especially regarding mobile service, depend largely on each carriers’ specific circumstances. And there’s no rule book but the one they write themselves.

Only last year, Dan Hesse, who at the time was CEO of Embarq, told me the “number-one” pillar upon which his company’s future success would rest was the right integration of wireless and wireline service. The urgency of that strategy was articulated in large part by the company’s precipitous loss of access lines, which are, one could say, the foundation upon which any pillar of success must stand. Mobile migration has been a primary cause of Embarq’s line loss, and yet the company’s adoption of mobile services in partnership with its former parent, Sprint, didn’t stem that tide. After two years, reselling Sprint’s mobile service yielded only 112,000 customers, just a fraction of the number of lines Embarq loses in a typical quarter alone. And so Embarq rightly cut its own cord, ending the partnership.

That move came just weeks after Comcast and Cox also dumped their Sprint partnerships, citing a lack of consumer interest. But consumers haven’t given up on the quad play. While less than 20% of those with bundled services have a mobile service included, 43% of respondents in a recent survey by Compete said they would consider getting a quad-play bundle. But they need to be convinced of the value of such an offer by carriers who can iron out the operational logistics needed to deliver that value.

Earlier this year, fiber-based triple-play provider SureWest Communications sold its wireless business to Verizon after determining that an in-house wireless offering was unnecessary and, by the way, too far afield from the triple-play business anyway. With a high-speed fiber-access network, SureWest has less to fear from wireless substitution. But its addition this year of a remote home-monitoring service is an example of what other carriers like Embarq need to do: Add value to those land lines that make customers less willing to give them up.

The US telecom industry has grown accustomed to letting AT&T and Verizon pave the way in many areas of technological innovation. But those two carriers will likely drive innovation in areas that capitalize on their unique business structure as true quad-play providers. The innovation that most carriers need, they’ll have to drive themselves.

E-mail me at ed.gubbins@penton.com.