Again why the attitude? They have huge pull in American multinational investment decisions, what's there to lose from getting them involved with Ireland more?
What's this got to do with California?
It doesn't make sense to not at least try getting some of them on board
As for California, if this business group is interested in trying to fix a sclerotic political system and terrifying public finances, they don't have to look any further than their home state.
Finally, the very existence of such a large Irish diaspora is in part to the preferences of Ireland's politicians - better to export the restive than have them stay and force reform on the system. The Irish political elite have never had an interested in what the diaspora had to say unless it involved steering money to the island, or favorable political and economic treaties from Washington.