You raise good areas of concern, and all of these things concern me too, but imo everything is ultimately surmountable.
I think a no deal would focus both sides on reaching agreements on these things. i.e. the EU would be ****** if we aren't buying their food / medicine so pretty sure there would be an emergency trade deal knocked up in 5 seconds. Same for freedom of movement -- it suits everyone for British / EU citizens to stay put. Also, we technically don't *have* to enforce a border in Ireland... if Ireland and NI just don't do it who will stop them? (I've lived near Gibraltar before and there were extended periods where neither side policed the border, nobody said/did anything).
Re: Jobs, we could make more favourable rules than the EU actually increase incentives for financial firms to be here. Same with cars, or any industry. We can undercut the EU at every turn and gain business.
The current problem is that asking "permission" it's too easy for the EU to just say no. Once these agreements benefits them they'll be falling over themselves to negotiate. The end result would likely be similar to a Norway deal.
However, there is a massive caveat: We could have spent 2 years planning all this to ensure minimal disruption.. and doing it as an "emergency" does hugely increase the short terms risks.
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I would be 400% for the EU if the currency, social benefits, healthcare etc was standardized throughout. But having lived in different countries it seems like everywhere else is taking the **** and ignoring rules, expenses etc. while UK citizens get a rough deal and everything is done to the letter.
I don't see how we can be in the EU when we don't even have the Euro, or when millions flocks here for benefits / healthcare. (Which also messes up many cities whose young population are leaving). They should get the same in their existing country.
I'm not saying your (or anyone else) opinion is right / wrong. Just sharing mine