It could do. One of the factors would be which airports get the facility.
If it's less hassle and stress for passengers to drive to a faily quiet UK regional airport, fly on EI/EI-R to Dublin, do pre-clearance there and then onward to the US compared to getting to a UK busy hub airport, check-in and pre-clear at a LHR/LGW/MAN et al before jumping the pond, then pax may choose the Dublin route.
IMHO, it all depends on how the transfer & pre-clearance experience is at Dublin.
JAS