I read that article. As a Yank I found it interesting. That Newstatesman seems to be a site pretty far to the left, so I assume it's representative of the Remainer position.
From my limited POV, the article seems to boil down to one simple issue: Tariffs. If the UK leaves the EU, the EU will impose high tariffs on the UK and the country will suffer for it, and this situation is similar to Venezuela's current trading status.
Fine. But it seems to me that what's really happening is a hostage situation. "That's a real nice economy you got there, be a shame if anything were to happen to it." I know, that's over simplified, and the EU could be justified to be angry at the UK for upsetting the applecart, but there it is. If the EU were not to impose high tariffs on the UK, the problem the article discusses would not exist.
I do understand that the EU pols don't want the example of Brexit to happen without cost, because that would tempt other countries to do the same. And that leads to the primary issue: Is the EU as constituted a good thing, or isn't it?
As I say, I'm a Yank and have no dog in this hunt. Whatever happens will happen. I figure that Brexit will cause a lot of trouble economically, and even more politically, but it's politics that caused Brexit in the first place, and not doing it will lead to even more politics of the same sort. No matter what happens it will be messy as hell.