Oh, goodness, what a question, and where to start? Appalling leadership (often absentee, like the rest of the Anglo-Irish bigwigs) Association with Englishness rather than Irishness Language - an English liturgy in a Gaelic nation An ingrained rural dedication to the old ways, such as lasted for many years in the North and West of England. The class divide, such as that which later fed into Methodism in England.
You are obviously a well-informed onlooker! In fact there was a conversion drive in the nineteenth century ("The Second Reformation") but it was not very successful. Also the Church of Ireland suffered badly through the scandalous (now revoked) RC doctrine of ne temere whereby the children of "mixed marriages" had to become RC. But the Church of Ireland remains the second largest church on the island of Ireland as well as in the Republic, where it is enjoying a mini-revival. There is an interesting parallel with The Church in Wales, now an independent, non-established part of the Anglican Communion. Owing to the efforts of Bishop Morgan and others in the sixteenth century, both the BCP and the Bible were translated into Welsh at an early stage, with great benefits not only to Anglicanism but also to the Welsh language. Attempts to force Anglicanism on to the Protestant Scots failed, and their national Church, the Church of Scotland, remains Presbyterian.