No use serving everybody if they won't use it.
I'd hardle call annual 135m passenger bus journeys for Dublin Bus in 2008 a lack of use. Where service levels have increased so too have passnger numbers; if the 46A QBC can be a success it can work anywhere in Dublin.
Car drivers will not use buses.
That assumes that congestion levels do not increase, parking levels increase and parking prices stay static or fall. If bus services were upgraded in tandem with some affordable rail improvements; the so called car drivers that you speak of would consider their options provided they live and work within areas of a sufficient scale. If people choose to live in Virginia and Work in Rathcoole then the public transport system owes them nothing.
BRT in Dublin streetscape, fantasy tosh.
Add the 95m passengers carried by Bus Eirrean to the 135m carried by DB and you have a substantial number; denying the existing usage is uninformed. Even with an extensive tube network that carries 1.1bn passengers per year this impressive statistic is dwarfed by the 6.1m passengers per day that travel by bus i.e. 2.2bn or twice as many bus journeys as tube journeys in London.