You can have your own personal history if it comforts you, but as it happens this seems to be fairly well known accepted universal historical facts. So I guess I want to say that it was not a fair description, and that a few minutes of search had been due diligence on your part. Now I had to do the dive instead, since your claims came off as so politically biased:

According to Wikipedia the proximate cause was the blight in Europe, with longer term causes being absentee landlordism and single-crop dependence.

As for the rest, archaeologists has recently claimed that our society has been capitalist since the merkantilist tradition that grew from bottom up along what was later to become known as “The Silk Road” replaced grain weights with metal currencies. So I don’t think that could feasibly be behind the landlord system. (Capitalism being, like democracy, “the worst of systems apart from all the others”. And both needs a judiciary system to be fair enough.) It is a new result [reported in Science IIRC] so I’m not sure it is consensus.

In this case it seems it explicitly wasn’t due to our capitalism: “In economics, an absentee landlord is a person who owns and rents out a profit-earning property, but does not live within the property’s local economic region.” In Ireland at the time that property (not capitalist based) ownership was a result of politics, the medieval churches having political power: “During the course of 16th and 17th centuries, most of the land in Ireland was confiscated from Irish Catholic landowners during the Plantations of Ireland and granted to Scottish, Welsh and English settlers who were members of the established churches …”.

The dominance of potato had proximal and distant causes too, which had nothing to do with the landlord system. “With the “expansion of the economy” between 1760 and 1815 due to the Napoleonic Wars (1805–1815), which had increased the demand for food in Britain, the tillage increased to such an extent, that there was less and less land for small farmers, and the potato was chiefly adopted by the people because of its quick growth on a comparatively small space.”