Una was one of the people howling with rage in the late 90s that all apartments were not dual aspect and were "too small", around the time they changed the minimum size of a 1 bed to 55m2 with a stipulation that the majority in any development were supposed to be 10% bigger again or 60m2, which is nearly the size of my 2 storey 2 bed house.
I lived in loads of these, good bad and indifferent. They had many quality issues but the main issue was usually that they were poorly managed and it only took one bad tenant to make everyone else in the building miserable. BER ratings didn't matter quite so much when the place was quite small & ESB prices were a lot less than they are now. They were typically around 10-20m2, much smaller than even the smallest 1 bed apartments.
Its not entirely true that "landlords" ended up benefiting from this - it happened at a time serial landlords were in financial difficulty as lenders started calling in interest only loans or other businesses started running into difficulty. I recall a former landlord, whose top storey flat I'd rented from 02-04, put that house on the market for 600k in 2008 - it failed to sell, & he took it off the market. I see from PPR it eventually was sold, in 2014, for 80k. I recall overhearing a solicitor working for one bank in 2014 mentioning he'd put 300 investor repossessions in that day.
Una isn't looking at the cold hard realities facing many of the "old school" pre 63 units now: if they were merely "dated" in my early days of renting in 1999 compared to purpose built apartments, they are positively antediluvian now.
Here's a good example - guide price of €995,000. No mention of what price tag would be attached to make it meet minimum standards now, but suggestion a full restore priced 300k would bring it back to 1.5m in value, or upgrading as flats would command annual rent of 120k. It did sell,
but for 840k. Why so cheap? You can work that out from
the original advert here: the original 1963 declaration had it as 6 flats, but in 1983 the then owner designed to redo the layout & changed it into 8 flats, which made it non compliant from a planning perspective. They, or any subsequent owners, then failed to maintain the property, as you can see in the photos. Hence the lower than expected selling price.
Its really hard to extrapolate from census or PPR just how many of these are still in use, but last census seems to suggest about 50,000. I would imagine there are very few prospective landlords with 1m+ burning a hole in their pockets to buy up & refurbish, so I imagine all of these are being bought by some kind of institutional investor, refurbed & then re-let.