Wrong.
T-Mobile is gaining ground on all carriers if you look at the #'s they are making money hand over fist and are re-investing in property left and right. Just wait.. because T-Mobile is coming out with some crazy stuff soon that will turn the market upside down.
http://bgr.com/2015/08/04/t-mobile-vs-verizon-vs-att-wireless-revenue-growth/
As you can see, T-Mobile was the only wireless carrier to post any year-over-year wireless service revenue growth (+11.1%) in the second quarter this year. AT&T came relatively close to breaking even with -0.2% year-over-year service revenue growth but both Verizon (-1.8%) and Sprint (-7.6%) were both deep in the red.
And T-Mobile isn’t just smoking rivals in wireless service revenue growth but in other metrics as well. For example, here are the numbers for overall wireless revenue growth.