I can't speak to Ireland, but at least in Canada, between 1990 and 2020, rent increased by about 1.6x whereas house price increased by about 6x. I personally be

I can't speak to Ireland, but at least in Canada, between 1990 and 2020, rent increased by about 1.6x whereas house price increased by about 6x. I personally believe that declining interest rates are responsible for this decoupling. This also coincided with an increase in investor ownership, just as you suggest. Interest rates have started rising recently, and we are now seeing a rapid growth in rent costs while housing prices have basically flatlined or fallen slightly. This makes sense if you relate the two in terms of the price a rational investor would pay in order to own an asset providing a certain stream of rental income.