If Fisk ever does catch Matt, yeah, the fight will be over for Matt. It's really way too soon to say, but right now it wouldn't seem bad to me if Fisk got Matt (maybe he locks him up somewhere while he decides what to do with him, or to torture him), unknowingly putting everyone else in motion. James, Retsuko, (others?) would have to act together to rescue Matt/make Fisk go down for good. (I need happy endings so they would succeed.)

But anyway. One step at a time xD