I'm doing what most Europeans are doing here currently: Hope for Scottish Independence!
Seriously, though, those EU people here that I know (as I said, mostly freelancers) are working multiple dayjobs to earn as much money as possible to then escape.
From my anecdotal evidence (from the arts freelancing sector), most Germans have fled already, with French people on the decline as well. Still "lots" of Spanish people around, but my Spanish friends hardly see the point in being here anymore.
The Polish people I know just really really really hate Poland, and have small businesses here, so, it's tough to let that go to be honest.
My English friends on the other hand, kept telling me "that it'll be alright". My Scottish friends are getting ready for a revolt. The city is suffering a lot, and it will get worse and worse the closer we get to March.
Nicola Sturgeon is a great politician, and without her, I probably would have taken my chances of just moving over to Germany blindly.
Understandable if they do, although not sure if it is so much that they hate Poland, or it is that the UK is at a ridiculously better financial position than Poland, Poland has seen tremendous growth and is seen as one of the success stories of the EU, but it is still a relatively poor country, in the event of a no deal brexit the UK will still be far richer than Poland, and a good chunk of other EU countries for that matter, obviously for French and German citizens it is a vastly different story, since France and Germany are arguably better than the UK regardless of how things turn out (obviously for some fields and in some aspects the UK is better).
It is not like Polish people have much reason to hope for a better future in Poland given what it is happening there right now, there is clearly a power grab on the Judicial system which tends to be the first step for far worse things, things which Poland has some recent experience in, so yeah if they currently hate the prospect of going back to Poland I wouldn't be too surprised, no one wants to live in a country that is ever closer to a dictatorship like state.
I feel the above is a bit disenginious. I am Portuguese so my point of view might not be the best.
From the laws I saw, a hard Brexit requires the EU to have borders with the UK, even if all the laws/regulation are the same. The issue is not having a treaty and not about laws/ regulations being different. Do note that if I am not mistaken if the UK uses a WTO deal with "open" borders it needs to do open borders with all members of WTO and not just the EU. In short what I mean is that from what I understand goods being blocked are "law" problems and not whatever other excuse people use.
Forecasting the economy is hard and not perfectly precise but at least for Portugal it generally is relatively accurate. Using your analogy if the weather forecast cast is 80% rain and 5 degree Celsius you very likely won't have a very hot summer sunny day will you?
I am a doctor so that is my understanding of hard Brexit, the laws I deal with are much smaller so it is hard for me to see all angles. Hopefully someone that works with EU can provide better insight.
IMO your post is desigenous because while it makes "logical" sense it seems to ignore a lot of reality on purpose. (Starting with another point, ignoring laws and finally misinterpreting a weird analogy)
Now, maybe from the UK your post makes more sense but for those that leave outside like me it feels misguided.
Yaps under wto rules the UK cannot give preferential treatment to the EU (without and FTA), so to accept goods tarrif free from the EU it needs to accept goods tarrif free from the rest of the world, same as the EU to accept goods from the UK tarrif free it must also accept goods tarrif free from the rest of the world, which is obviously not going to happen.
So yeah it isn't just a question of good will and trust, the EU and the UK would have to quite significantly violate international law, not to mention the EU would piss off all the other countries they have FTA with, and even its own members since it would be giving one of its membership privileges without getting anything back, it would basically be giving preferential treatment to a non EU member over its own members which is obviously crazy.