Don't forget that part of the merger was Dish buying Boost Mobile with the supposed intent to build their own network. Which anyone actually paying attention knew would never actually happen. Dish Network says a lot of shit, and follows through with basically none of it.

On July 1, 2020, Dish Network officially purchased Boost Mobile per their agreement with the companies and the United States' Department of Justice. The purchase was valued at $1.4B and transferred 9.3 million customers.[67] The intent of the US government was for Dish to erect a new nationwide wireless mobile network in order to compensate for reduced competition following the Sprint–T-Mobile merger.[citation needed]

However, in the years following the transaction Dish failed to sufficiently grow Boost Mobile's subscriber base and in 2025 announced that it will decommission its 5G network infrastructure, sell most of its wireless spectrum assets to AT&T, and shift Boost Mobile's operating model from a facilities-based network to a mobile virtual network, with its subscribers being hosted on AT&T's wireless network.[68]

T-Mobile followed the timeframe they agreed to for the merger to be approved, which was very public.

On March 11, 2020, California Attorney General Xavier Becerra announced he will not appeal the judge's decision made during the previous month to reject the state AGs’ lawsuit against the T-Mobile-Sprint merger. He, instead, struck a settlement with the defending parties. The terms of the settlement include making its low-cost T-Mobile Connect plans available in California for at least 5 years, that T-Mobile customers can keep their T-Mobile plans held in February 2019 for a total of five years ...

Hmm... 2020 plus 5 years is... 2025... would you look at the calendar.