NAMA is not in any way responsible for the housing crisis. Its purpose was not ever to fund or incentivize homebuilding and in any case, if I think back a decade, to a point where NAMA had been in operation for five years, there was no housing crisis. Neither NAMA nor the Troika ever discouraged housebuilding. Even if it had been a policy of theirs, there wouldn't have been any need: a sizeable proportion of the building companies here went bust after the 2008 crash and their employees had to emigrate or retrain. Furthermore, none of the local banks were in the financial position (or the mood) to fund property development.
The Irish housing crisis has very simply and abruptly come about because of the massive growth in population that has occurred here over the last nine or ten years. Due to the catastrophic implosion that occurred in the indigenous building industry after 2008, speedily ramping homebuilding up to a level that can keep pace with inward migration is essentially impossible.
We may eventually be able to build fifty thousand dwellings a year, but the shortages will persist until then. There are other factors that exacerbate the problem, most notably our sclerotic planning system, but the fundamental issue is the hollowing out of the private construction sector that occurred at the start of the last decade.