^ Another big advantage the Borg have is transwarp. It means the Borg can reach them but the Dominion can't strike back at the Borg. The Dominion can't impede the Borg's ndustrial capacity if it can't strike at shipyards, command centres, dilithium production centres. The Borg on the other hand can hit Dominion shipyards and more importantly they can hit KW production facilities. You mess with that and the Dominion is in real trouble.
That reminds me, in DS9 we see Sisko and co go after the main KW production place and destroy but we never see any consequences of this, which I found a bit disappointing.