There is far too much talk of conspiracy, incompetence or allegations of lack of decisionmaking on the thread. I would rather assume people did their jobs to keep us all safe until proven otherwise..
Given that volcanic activity is know to be a problem to air travel, that iceland is a very active island upwind of Europe and that there was NO orchestrated, pre-planned response to measure the cloud and refer to established and agreed levels of risk then the airline industry, aviation bodies and governments are at least lazy if not incompetent.
That there isn't some organisation or another coming out of the woodwork saying "I told you so" is also surprising, perhaps researches thought that the airline industry could look after itself?
Mickjoebill