Although T-Mobile has framed its plans to launch in-home broadband Internet services as a major threat to the cable industry, some Wall Street analysts aren't buying it.

"Home broadband is one of the most un-competitive industries in existence. The New T-Mobile & 5G can and will change all that," T-Mobile CEO John Legere boasted last month of the company's plans to launch fixed wireless services across the country.

But the analysts at New Street Research don't believe cable companies need to be worried. "The impact of T-Mobile capturing home broadband share is immaterial to fixed broadband companies generally, and cable companies in particular," they wrote in a recent report to investors.

At the heart of the issue are T-Mobile's efforts to consummate its proposed merger with Sprint. The company has argued that, if it is able to acquire Sprint's extensive 2.5GHz spectrum holdings, it will not only challenge AT&T and Verizon in the mobile 5G market but will also use the spectrum to launch a 5G in-home Internet service that will directly compete against services from wired Internet providers like Comcast and Charter.

"The New T-Mobile is coming for you, Cableopoly," T-Mobile's Legere bragged of the company, dubbed "New T-Mobile," that would be formed through the combination of Sprint and T-Mobile. "You've been warned!"

But the New Street Research analysts said that they crunched the numbers -- in terms of customers' in-home Internet demands, wireless network capacity and market pricing and dynamics -- and found T-Mobile's threats to be mostly bravado with little substance. "Our analysis demonstrates that, while T-Mobile's merger with Sprint will create significant capacity for pro forma T-Mobile that will make them a formidable competitor in the wireless market, the opportunity for them in home broadband is small, and the threat they pose to existing broadband providers is smaller," they wrote.

Specifically, the New Street analysts concluded that the combination of Sprint and T-Mobile would only have enough network capacity to support 7.6 million total in-home Internet subscribers -- the firm said T-Mobile estimates the average household will consume around 500GB per month in 2024, but the New Street analysts believe it will be more than double that figure based on the growth of streaming video. Further, the analysts predict that T-Mobile will only be able to sign up around 5.3 million subscribers -- roughly 4% of the market -- to its home Internet service by 2024.

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Those figures are far below T-Mobile's own expectations of creating capacity for 13.6 million customers and actually signing up 9.5 customers in 2024.

Interestingly, the New Street analysts pointed out that it would be much more profitable for T-Mobile to simply use its excess network capacity to chase mobile customers, not in-home Internet customers. "Carriers generate ~37x the revenue on a GB sold in the mobile market than on a GB sold in the home broadband market. As such, they would never use wireless network capacity to attract home broadband customers, unless they had considerable excess capacity," the analysts wrote. "T-Mobile would be far better off using that capacity to add more wireless customers rather than home broadband customers. The same capacity would support 13MM wireless subs, which would generate $6.3BN in revenue and $4.4BN in EBITDA. For T-Mobile shareholders, the 11MM wireless subs would be worth 2x what 5.3MM broadband subs would be worth."

That said, the analysts don't completely discount the competitive threat posed by T-Mobile. The firm said that T-Mobile could cut out roughly $4.3 billion -- or 1% of the total -- in revenues collectively from wired broadband providers' balance sheets.

T-Mobile, for its part, is using its fixed wireless Internet plans in part to convince regulators at the FCC and Department of Justice to approve the company's proposed merger with Sprint. Essentially, the company's argument is that the transaction would increase competition across the telecom market -- opponents to the deal though argue the merger would reduce competition in the space. Although analysts in general initially believed T-Mobile would likely be successful in its attempts to merge with Sprint, some have recently lowered those expectations based on increased opposition to the transaction. For example, Bloomberg reported recently that a number of states are gearing up to potentially file a lawsuit against the merger.

Nonetheless, T-Mobile is moving ahead with its plans to merge with Sprint and launch a fixed wireless Internet service. Indeed, the company recently disclosed plans to offer LTE-based fixed wireless services to up to 50,000 US households by the end of this year, a plan that sits outside of its merger efforts but that T-Mobile said will help set the stage for a broader rollout of the service using Sprint's 2.5GHz spectrum and 5G.

— Mike Dano, Editorial Director, 5G & Mobile Strategies, Light Reading | @mikeddano