@Sskka "They [Croatia, Slovenia, Slovakia, Czechia etc] were nations already, why wouldn’t such a thing have been possible?"
These were not already nations (in 1990-93) and had hardly ever existed as independent countries at any time during the previous 1,000 years.
" ... leaving aside collapse of the Soviet Union, which isn’t exactly a parallel to anything we’re talking about here"
The collapse of what remains of what was once, just 150 years ago, the wealthiest and most powerful Empire on the planet would certainly be a major event in world political history. Although the Irish State came into being in 1919, the Republic of Ireland in its current form has only existed since the Republic of Ireland Act of 1948.
If history has taught us one thing it is that things do not remain the same for ever.