That is true but if those countries outside the EU still want into the UK market they will have to do a separate deal.
The UK is unlikely to break up because of the underlying economies especially pensions issues. It is however possible that a new UK is formed of four truly independent countries (assuming a 'All Ireland' solution could be 'manufactured' at least on economic grounds, that would still maintain the GFA principles, this of course would be the temptation to Ireland to as it were ...Irexit' from the EU, unlikely but possible!
We all know you are the 'Project fear' leader in chief Paul and you may well have an opportunity to gloat later (next year); however I do agree with you that many over here now seem to be ignoring the WA and working on the assumption that if eventually there is a no deal outcome then the WA gets washed away with everything else, which is a reasonable assumption, Remember Theresa Mays words about "Everything is agreed, or nothing is agreed."
Yes that's the whole point, the UK will have to negotiate deals with every country throughout the world who are willing to have a deal with them. The EU don't, they already have them. The UK have got a lot of negotiating to do which would be difficult enough with people who know what they are doing, I can't think of anyone in the British government who gives the impression they know what they're doing.
The GFA principles are being satisfied, otherwise there wouldn't be a negotiated Withdrawal agreement between the EU and UK, as I said the border is effectively in the Irish sea and now one part of the UK has to export to and import from another part of the UK, well done Brexiters.
This "no deal" is not about the withdrawal agreement , it's about the new trading relationship between the EU and the UK and the transition period was due to be around two years which was intended to smooth the process where the UK still benefited from the EU whilst trying to start negotiating new trade agreements with other countries which you acknowledged at the start needs to be done. As usual the Brexiters have c*cked that up as well so we're now four months from total departure and the UK have nothing. The three agreements they were trying to start off negotiating, with the EU, USA and Japan all seem to have hit the buffers.
My view , as it has been since the beginning is I don't see how possibly this will work and has nothing to do with Project Fear, it's not about gloating either, it just seems inevitable unfortunately and always has done. Even if the UK sign a trade deal with the EU, I don't see how it will work if they are not in the same Customs union.
Why the UK think other countries would leave the EU I have no idea, why does the UK think the EU will break up. Does the UK think ECOWAS , the West African equivalent of the EU will break up? This involves Commonwealth countries such as Ghana and Nigeria for example, talks between the EU and ECOWAS started in 2004, most of the ECOWAS countries have signed the EPA but not all, Nigeria haven't yet signed.
How quickly do you think ECOWAS will sign an agreement with the UK? In both our lifetimes?
Will the Pacific partnership break up, will the UK join the Pacific partnership, something a bit more absurd I suppose.
And at the end of it all, what is the benefit to the UK? How on earth will the UK be better off?