The issue is that farms attract EU and national subsidies of around €1.5 billion a year. They are to a large extent area-based payments, so once you can show that you have X hectares being farmed you get a direct payment. Non-dairy cattle farming is not very labour intensive and you can combine it quite easily with other work (dairy and tillage less so).
By now the majority of farms in Ireland are part time and in effect it is a very well subsidised hobby. You can look at CSO
agricultural accounts. Farm output less non-labour inputs (net value added at basic prices) is in most years less than the income from subsidies. When you take out paid help farmers make about twice as much in subsidies as they do in profits on their farm activity.
In many ways farming is more passive than active income. The land is doing more work than the farmer is, mainly by attracting subsidies. If the subsidies disappeared a lot of land values outside dairy areas would collapse.
I can see a case for lower inheritance taxes on large, intensive farms that are essentially family businesses and worked intensively. For the hobbyists out there - and there are many - the inheritance tax regime is way too low.