Has T-Mobile really kicked off a mobile price war, or is it all just an illusion?

In the year since T-Mobile(s tmus) launched its Un-carrier campaign, it’s triggered a lot of changes in the way we buy phones and mobile service in the U.S.

Every major carrier now has some sort of upgrade program. The subsidy costs of our devices are increasingly being separated from the monthly rates we pay so we don’t get double-billed for our handsets. And many carriers have responded to T-Mobile by dropping prices on key mobile data plans.

But are we seeing a price war? I have been saying yes because I see more new options opening up in the market that allow consumers to pay less on monthly mobile phone bills or get more bang for their buck. My friend Phil Goldstein at FierceWireless, however, disagrees.

In a post earlier this month, Goldstein pointed out that the average bill for a U.S. mobile subscriber has gone up more than $5 per user in the last three years. Meanwhile, AT&T(s t) and Verizon’s(s vz) margins have barely dipped, and their profits certainly haven’t suffered. If a price war means competitive pressure, the carriers aren’t feeling it in on their bottom lines.

What we’re seeing, Goldstein wrote, is changes in pricing structure: the amount we pay remains the same, it’s just shifted from service plan to device or from data to voice. While there may be more cheaper options out there, the plans are structured in such ways that most consumers wind up paying the same rates. For an example of a true price war, Goldstein says we should look to France, where Iliad’s Free Mobile has forced dramatic price cuts in basic voice and data services.

Goldstein has definitely made me reconsider my stance. If “war” is the operative word here, we’ve really only seen a few opening shots exchanged, and neither side has suffered any real casualties. Still, I don’t think we can completely dismiss what T-Mobile has set in motion.

Two years ago, AT&T and Verizon were restructuring their pricing models through mandatory unlimited talk and text plans that actually raised rates on many consumers. They were still charging you fees for your phone even after you had paid it off. The cost per gigabyte was rising, despite the fact the carriers’ new LTE networks delivered those gigabytes far more cheaply.

Now that trend is reversing — maybe not to the extent that the carriers’ profits are suffering, but things have finally started to happen in the stagnant U.S. mobile market. What’s more, these opening volleys could escalate into the true price war Goldstein is talking about.

T-Mobile CEO John Legere kicking off the iPhone and T-Mobile's Un-carrier plan last March

T-Mobile CEO John Legere kicking off the iPhone and T-Mobile’s Un-carrier plan last March

In a recent report, mobile industry analyst Chetan Sharma said that T-Mobile has taken the calculated risk to lure in customers by lowering prices and operating at a lower margin. To keep that strategy going, it has to keep its subscriber base growing to make up for lost revenue. If and when T-Mobile’s competitors match its pricing, then the balance is restored, so to keep growing T-Mobile would have to cut its prices even further, again forcing its competitors to react, Sharma pointed out.

“In a saturated market, once a player decides to operate at a lower operating margin, it triggers the value destruction in the industry, which can be sometimes devastating to incumbents,” Sharma said.

Japan's SoftBank Corp. founder and President Masayoshi Son speaks during a press briefing to announce the company's financial results in Tokyo on February 12, 2014. SoftBank said February 12 its nine-month net profit soared 58 percent thanks to strong iPhone sales, but third-quarter earnings suffered because of losses in its newly acquired Sprint Nextel unit. KAZUHIRO NOGI/AFP/Getty Images

Japan’s SoftBank founder and President Masayoshi Son kicked off Japan’s price war and is now targeting the U.S. market through Sprint (source: AZUHIRO NOGI/AFP/Getty Images)

We’ve seen it time and time again. Reliance Communications started India’s ongoing price war in 2002. Masayoshi Son triggered it in Japan in 2008 after his company SoftBank bought out Vodafone’s operations (Son has promised to do it again in the U.S. if regulators let him merge T-Mobile with Sprint(s s)). And most recently it happened in France, when innovative broadband ISP Iliad entered the local mobile market.

So maybe we don’t have a true price war in the U.S. today, but we definitely have the makings of one, and it’s long overdue. Compared to other developed markets, the U.S. pays enormously high mobile fees (and produces the most profitable mobile carriers in the process). If T-Mobile and its confrontational CEO John Legere can erode those rates – even only incrementally – then more power to them.