If Iliad were to acquire T-Mobile for $15 billion, the French carrrier would likely bring its discount model to the United States. While great for consumers, that model drag on U.S. carrier revenues. 

According new research from Strategy Analytics, Iliad's "Free" has had a dramatic impact on the French market, driving a 29 percent decline in service revenue and 19 percent decline in EBITDA since its launch. Strategy Analytics also notes that Iliad’s founder, Xavier Niel, is also an investor in Israel’s Golan Telecom, which staged an aggressive mobile launch two years’ ago that has since had an equally dramatic impact on that market. 

Susan Welsh de Grimaldo, director of wireless operator strategies at Strategy Analytics, said that while T-Mobile’s Un-Carrier strategy has elevated its market position, its second quarter performance trailed AT&T’s and its transformation has been more about offering customer choice and flexibility rather than lower prices.

"Iliad’s Free strategy is all about the price," Welsh de Grimaldo said in a statement. "Pushing multi-play bundles would be an obvious response for Verizon and AT&T to the Free approach, a strategy which has enjoyed some success in France, but that is currently not an option for Sprint.”

Phil Kendall, executive director of wireless operator strategies suggested that a successful Iliad bid would force the operators to move away from battles based on network coverage, speed, and pricing, and focus on effective marketing strategies built on segmentation. 

"But irrespective of T-Mobile’s ownership, this is a wake-up call for operators to get ahead of the game: differentiated products targeted at specific market needs," Kendall said in a statement. 

All of this hinges on a successful bid, which currently seems unlikely given Softbank's appetite for T-Mobile. Strategy Analytics says that Iliad would likely back down from a bidding war with Masayoshi Son and company. 

Already investors are souring on Iliad's bid, with some saying it's too low. Shares of Iliad were down nearly 2 percent in trading Monday to $188.