A key part of the issue in dublin is the developers claim that they cannot sell affordable housing at a profit. The main costs they point at being government taxes and levies and the cost of land.
The land issue could be handled by opening up cheaper land to commuters through improved public transport. Or increasing the turnover of land through vacant site levies.
Many people also point to offering a temporary VAT increase to "kickstart" development or reduce development levies, though a criticism would be that woudl simply funnel money to the developers and not result in any affordable housing.
Any developer led initiative though would take some time to ramp up. A government led program of soical housing would be much quicker. Though many people would be opposed to this as they have an interested in the currrent housing shortage and its role in driving up property prices. There is also the role of NIMBYISM that causes huge delays in the planning process.
A good site for reading up on these issues is http://www.dublininquirer.com/2016/03/23/in-dublins-housing-crisis-bureaucracy/