> Because Kaliningrad Oblast is small, homogeneous and an exclave within the European Union, in 2011 the whole Oblast was granted the status of border area eligible to local border traffic rules.
- https://en.wikipedia.org/wiki/Poland%E2%80%93Russia_border
- https://en.wikipedia.org/wiki/Enclave_and_exclave
- https://en.wikipedia.org/wiki/Local_border_traffic
NI is not an exclave. There may at some point be a "local traffic" agreement with between NI and The Republic of Ireland, but that is something that needs to be negotiated.
That this negotiation hasn't finished yet is because the relationship that the UK will have with the EU is still rather up in the air. The EU wants a border so it can maintain import duties with external countries, exclude dangerous items and people, and maintain compliance with things like food standards (think lowering of food standards to make a US trade deal possible). The UK wants a border so we (well, not me, the people who voted for this ill-conceived shitshow) can keep immigrants out, and also to collect customs tariffs, block etc. etc. etc.
The requirements that each negotiating position has, as well as the general desire to not trigger a recurrence of "the troubles" are really hard to solve. There are literal opposing requirements that somehow need to work together.
If you take that, and the fact that the UK needs the EU way more than the EU needs the UK (the "UK holds all the cards" blithering of the tea with vicar dancing round the maypole cricket on the green little englanders aside), then you realise that the EU doesn't really need to do anything. It's not going to "throw us a bone" on this, it's going to use it as a negotiating position, and the UK will eventually either give some ground on another issue (freedom of movement perhaps), or we won't and there will be a border.
You have to remember that this is what people voted for. If they didn't vote for this then perhaps they should have listened to "experts" more, and maybe people should be questioning the ability of politicians to so clearly lie through their teeth to get the thing that they want (eg. Boris Johnson: a conservative party leadership bid, "350 million per week" etc.)
The really really simple solution is for the UK to have full regulatory compliance with the EU, something like the Norway model, but all of the "models" have significant disadvantages, such as "pay with no say" as the Norway model is sometimes described. We could of course stay in the EU, that's actually been offered. We wouldn't have a border in NI, we would have access to relationships with other countries via the over 750 treaties that the EU has, but that it seems isn't something we want enough apparently.
edit
Just out of interest, what are your ideas as to how this should work?