T-Mobile has a ton of momentum right now, and it appears that the only way that momentum could slow down is if they don't get their network built out. It's no secret that T-Mobile's network isn't the strongest or the largest in the US. Although that has changed quite a bit in recent years. T-Mobile has been picking up 700MHz spectrum left and right and continue to grab more and more spectrum licenses. The company also launched their BallBuster Challenge recently, to show users in areas that most don't think T-Mobile has coverage, that they do have coverage and have pretty amazing speeds.
The company's Chief Financial Officer, Braxton Carter is speaking at an investor conference this week and stated that the company covers 305 million people in the US with LTE. He also noted that T-Mobile thinks they "have the opportunity to expand our distribution into another 30 to 40 million POPs here in the US where we have zero penetration." Essentially what Carter is saying is that they are looking to add at least 30 to 40 million on top of that 305 million. Which puts them into Verizon's territory, as far as how many American's they cover.
When T-Mobile bought the 700MHz A-Block spectrum back in 2014 (they paid Verizon $2.4 billion for a big chunk of that spectrum), many skeptics didn't think that T-Mobile could roll out coverage on those airwaves quickly. However, the company was able to roll out coverage on that band much quicker than Verizon had. Something that Carter was sure to mention at the investor conference. Verizon had 150 million POPs worth of 700MHz A-Block spectrum, and they never did anything to clear that spectrum. Carter noted that when they started calling broadcasters who used the spectrum before, to clear it, they stated that it was the first call they ever got. Proving that Verizon didn't even try to clear that spectrum. Carter also said that it was pretty easy and economical to clear it quickly.
Then there's the upcoming incentive auction happening this month for the 600MHz spectrum. That's spectrum that T-Mobile wants desperately. Previously Carter had mentioned that his company would commit to spending as much as $10 billion. However that amount may have changed, and Carter likely won't be making that figure public. As it could lead their competitors to outspending them just because.