The plantation of Ulster was incomplete by design.
Divide and conquer.
We’re all mere pawns in a bigger game, folks; living out pre-determined mindsets.
Britain could (one imagines without too much difficulty) simply have ethnically cleansed the entirety of Ulster of its existing inhabitants and sent many more of my lot to Connacht.
Instead, Britain chose to allow a dispossessed and numerically significant minority remain in situ. We usually had been kicked off the better land, but we were still very much around.
This partial colonisation made British control very simple. The dispossessed now resented the newcomers, and focussed their ire on the newcomers, instead of on the string-pullers in Britain. And the newcomers naturally then depended on London to protect their interests from the recently-dispossessed.
That avoided the “Old English” problem, where previous English colonists further South started (over a few generations) to self-identify as Irish and to resent London.
But leaving a significant minority of prior natives in place meant that both communities have been at each other’s throats ever since.
That cynical original structuring shapes us still.
We were structured so that both our communities would be in perpetual conflict, and we’ve generally managed to inhabit our contexts and to fulfil our charters, largely without awareness.
From a British administrative POV, it has worked extremely well. As this fairly-recent conference noted:
“The importance of this event to the shared histories of Ireland, Britain and the British imperial world would be difficult to overstate. It copper-fastened the English and British conquest of Ireland, and dramatically transformed Ireland’s physical, demographic, socio-economic, political, military and cultural landscape. In effect, the plantation became England, Britain’s and the City of London’s first successful attempt at plantation and the latter’s vigorous attempts to protect this investment would have enormous implication for the collapse of the Tripartite Stuart monarchy in the 1640s. Furthermore, it provided a successful template for British conquest, plantation and imperialism in the Americas, the Caribbean and the Indian sub-continent. Finally, its historical, political, cultural, environmental and visual effects have impact on the two cities and islands until the present day.”