Agree with your post but think even if you have an unlocked ATIV S T899m a FW update would still not be available unless via Samsung. This brings it back to Samsung being responsible for an update which I don't think exists for our phone. Pappale has stated his phone has rec'd both FW and SW updates for 8.1.1. but not confirmed the exact model he has. AFAIK no T899m anywhere has gotten these. If I'm incorrect on this then carriers should have access to the same FW and make it available to their customers.
Bell is still offering the ATIV S. Why would anyone buy this if support is discontinued? If they have inventory they are stuck with they should update FW and allow the 8.1 update install. Otherwise they are offering an EOL device with no update path and locked to an obsolete state. If they would provide the updates and reduce the price on the ATIV S they could clear out the old inventory, recover some costs, and satisfy their customers already invested in the device. Is there something in this logic that I'm missing?
Just read a reply from Pappale which confirms he has the Ativ S i8750 and not the T899m LTE version. I was hoping he did have the T899m as that would confirm FW actually exists. I am further convinced carriers don't have a FW update from Samsung for our LTE model.