I finds it fascinating that island of Ireland has its own language, Irish, with long and storied history and yet over time has lost it to English.
I'm no expert in Irish history, but even just the 20th century tells me that Irish are not the sort of people who would let the dominant power roll over them. Yet based on my understanding of the situation, if you were monolingual Irish speaker nowadays (or 20 years ago, not to run afoul of the rules) you'd struggle to live day to day in Ireland.
How did this come to be and was it an intentional effort? Have there been any even marginally successful revival attempts?
Here is an answer by u/EmmetOT that very briefly touches upon this. It might provide some background while waiting for a new, more in-depth answer.
I answered a similar question on This thread (you'll need to scroll to the bottom)