I’m not so sure that the mortgage rules are the dominant issue in the weakness in Dublin high-end, given that Irish banks post the GFC, don’t want to get into +1m mortgages (regardless of salary etc.), and have been reluctant to give them regardless of rules.
In naughties, the Irish law partner would get 6x total annual compensation (i.e. salary+bonuses) as a personal trackers mortgage (i.e. 6m), on the same terms that the Irish bus driver would also get on his 6x total annual compensation (i.e. only salary).
The lawyer’s earnings turned out to be unsustainable, while the bus driver’s durability was much better.
This is a lesson that US banks learned many years ago, and therefore “jumbo” mortgages (i.e. loans of over $800k) are separately regulated and costed for in the US market. Irish banks are so full of insolvent +3m mortgages that they don’t want any more “jumbo” mortgages - period.
A couple of private banks in Ireland, are running a side-line in “portfolio finance” loans where you get a rolling 3 monthly 1.5% tracker loan secured against liquid shares etc (you get +75% LTV). It’s not a mortgage (and can be withdrawn at a months notice, or if the shares fall materially in value - 2007 deja vu), but it has been appearing quite a few times in Dublin high-end (I would guess that 2 Shrewsbury Road is a very public case in point, and I can think of 2 other cases on that road as well).
Given that so much of the +2m market in Dublin is driven by non-domestic buyers (incl. ex. pats), I would suspect that international factors, and the slow-down in the insane London property market (as well as sterling weakness more recently), is more dominant.
Since the GFC, Dublin high-end has been very fragile anyway - so fragile that almost no Irish bank will foreclose on a high-end Dublin property (as the market can’t handle any more supply than current run-rate).
A modest fall off in even London based Irish ex. pats, would be a material problem in the high-end Dublin market.
Where as in 2014, when London property was at its peak + Sterling was also very strong, that was a key driver of Dublin pricing.