In the past phone were made in a way that the bateries could be easily removed and replaced like the phone shown above, made in 2002.
Now a person would be very hard pressed to find a phone with an external battery. Phones now have a battery that is trapped inside the phone cover, not easily removed for replacement.
T-Mobile is similair to many other companies, promoting a culture where working equipment is replkaced on a frequent basis. A culture that demands everyone should have the newest and best equipment.