I don’t think that the no-deal brexit would be an economic disaster in long term: there would be a short term chaos before all the stakeholders adapt to the new situation, but the trade would eventually find its ways if it is beneficial for both sides. It was able to do so in even more complicated cases, e.g. the case when Russia banned import of all agricultural products and groceries from EU, many EU producers found its way to export to Russia via Belarus, etc. I don’t think that such a drastic measures like ban in direct trade between EU and the UK would be applied and the corporations would sooner or later get used to the new administrative measures.
I agree with the article that the biggest long-term threat for the UK economy is that it loses the status of the gate to the EU single market for global corporations - and they may move their European HQ to other members, in particular Ireland and the Netherlands (that positions itself to replace the UK as the liberal trade-friendly country in EU). However, the UK may offset this disadvantage by offering favourable tax rates and promote itself as the new tax haven on the doors of Europe which may persuade many companies to operate in the UK, especially companies that don’t need to perform physical trade, like high-tech, services, etc.
And, of course, there are some threats not related to economy, in particular the situation in Northern Ireland where people may not be happy with introduction of new physical and mental borders. It will be interesting to watch how it will be develop but it will not anyhow affect continental EU members.