All business relies on other companies and government to supply goods and services.
The result is a network of supply paths.
I know that because of the multiple paths many consider this to be
a reason to believe the system is very resilient.

Can the increasing stress on the system result in a point being
reached where a breakdown may happen quite suddenly,
as a few critical companies or government organisations such as
railways, airport support, fuel supply cease ?

The collapse could be sudden and widespread over a few days.

Not can we reach breakdown Bazz, but when.

So many of the little blokes are already past survival, & it is very near when most of them will fail.

They have all their cards played betting on the jab to save us. When it doesn't it will be too late for any cure of the virus to save the economy. We are stuffed, & it is our own doing.

One thing that is evident during the pandemic is the inability of Capitalism to deal with a sudden economic crises brought on by a health crises, and the need for government to resort to Socialists measures to keep the economy on life support. Liberal debt is in the order of one trillion dollars, and growing.

Where are all the fiscal "experts" now ?

I have a recollection of reading about network theory like, what I
suggested above. It was something along the lines of a very large
number of network connections do not guarantee against collapse but
in fact make it susceptible to sudden collapse.

Paul, I think a socialist system as has already been demonstrated
can collapse without any strain at all !
I suspect it could never get too complicated because of the overhead
of the bureaucracy. They collapse before they get complex.

Never in human history have we been so inter-dependent on each other for survival and society itself is often like a deck of cards. The vast majority of the population is non-productive in a true sense and economies are dependent on consumption. People fighting over toilet paper today could as easily be fighting over food and clean water tomorrow under other circumstances.

In the end we can only be saved by governments because "the market" is incapable of getting us through this or any other global event.