Ireland and Greece were not supposed to be 'weak' countries.

Ireland just a few years ago was seen as a model for economic growth (supported by very low tax rates for companies). Ireland is a victim of its own misguided policies (housing bubble, banking system, ...) and its orientation to anglo-saxon economic policies.

Greece also failed to reform its economic policies (after cheating on the economic data for quite some time). There was time enough to do that.

I also don't think these countries are 'collapsing'. But adjusting their economic policies will be tough.