I’m amazed you would even consider that terminal care could be on the table ronib, it’s always been one of the fundamental things the NHS does.
Other treatments which are non life changing are always valid to consider for NHS funding, and there are already processes in place to do that, based on both political funding and clinical decisions.
Your point about A&E is erroneous. Of course, there is a level of abuse of the system - but A&E is not, and was never intended to be the gateway for hospital admission. The vast majority of admissions are organised between GPs and the relevant hospital clinical team. People who are involved in traumatic or emergency events go to A&E. you don’t need to be admitted to hospital if you have broken your wrist, or have a saucepan stuck on your head, or you’ve burned your arm on the iron, or whatever, you might if you have collapsed in the street, but after assessment you might not - that’s what A&E departments do, the clue is in the name.