the rule change doesn't really affect my wife and I much because we don't switch carriers or get a new phone very often. Our phones are all several years old and we have been with the same carrier for longer than that. But I do have a story that can illustrate a little closer what I think that the real issue is. Ten years ago we were using the same carrier that we had our land lines with for our cellular service. We were satisfied with the price and service up until they sold of their cell towers to Sprint.
They said that this would improve their coverage, but the Sprint towers we were now using gave first priority to Sprint customers. Even after several months most of our calls were dropped within a couple of minutes. It was explained to me that whenever all of the spots in the cell tower nearest our phones were filled up our calls would be dropped to make way for Sprint customers just coming on line.
We were quite happy with the expensive Motorola handsets that we had paid hundreds of dollars a piece for. We are careful with the things we own so they were in perfect condition and we had also purchased hands free adapters and external antenna connectors for our cars, along with extra batteries and cradle charges. We were out of contract... so after six months of frustration we decided to switch to Sprint. I assumed that we would be able to use our premium handsets that were already using the Sprint network.
No dice! Sprint forced us to buy new handsets. They did not offer the same type we had so we could use all of the accessories we had for them. We ended up getting phones that were twice the size of the ones we already had, but at least the problem with dropped calls went away. I almost decided to go with a different carrier, but we were already paying significantly more per month than we had been and I knew the towers worked where we lived... which can be a problem when you are in an outlying area.
I still have those expensive phones in a drawer along with a few others. Of course they are expensive paper weights if no carrier will let you use them. It bothers me that I cannot use products that I purchased for the use they were intended. This is actually about control. The contract carriers don't want you to be able to use even one of their older phones with one of the no-contract carriers. I am getting very tired of it and am about ready to give Sprint the boot.
Sorry to hear you got stuck with an uncooperative provider.
Not to point out the obvious, but did you try to just use your new Sprint SIM cards with your previous phones?
I’m not aware that the cell net would be able to discriminate between the phone devices if a valid SIM card is recognized.