1. DT would need to pick up Sprint's debt balance. 2. Sprint's towers's would be worthless to DT as they are a completely different technology. Sprint uses CDMA to T-Mobile's GSM. 3. If DT decided to keep Sprint's CDMA line of phones and towers open, they would probably have to create a completely different accounting system, is one of the reason why Sprint ran into problems when purchasing Nextel's IDN network. 4. DT has enough head aches of expanding and keeping customer service departments trained and professional than have to buy Sprint's ready-made unhappy customers.
Deal would be a nightmare for both entities in the short and long run.