Biggest wrong assumption - the one that is really worrying them - is that far more people than they expected stopped work if they could not WFH
It is a tricky one, isn't it? I think one of the problems is that if businesses don't have the ability to successfully implement social distancing, then they have just stopped trading instead. Our local bakery has closed for example (which is a right pain), as has the (indoor and permanent) food market.
Beyond that - people are also making assumptions about businesses being closed/unable to operate. I have a SE friend whose business is able to operate as normal, but who has had no new clients for the past 3 weeks because everyone is assuming they will be closed.
There are loads of takeaways round here that are closed too - presumably because they were not getting enough trade to make it worth opening.
So it is not just a matter of people deciding to work from home - there is also the issue of people assuming businesses aren't operating.
When it was first announced it was the most confusing message. E.G. self employed joiner ( not really essential) should they have been working? According to MN - no - but the guidelines were so ambiguous. Now we have lots of people isolating and not earning money and who will claim for furloughing of staff and for themselves being SE.
It's going to bankrupt the country!