And note that for all aircraft the landing distance is calculated _without_ thrust reversers or spoilers, and thus is based on braking performance alone.
Some of the challenge here was the seconds spent at near landing speed without any braking being performed, as that'll eat up runway distance fast, following the auto brake failure prior to manual braking commencing.
It's also worth stating (for the OP) that thrust reversers are potentially really dangerous -- if they deploy in flight without being commanded to, the aircraft can -- or, more likely if the engine computer does not detect it and shut itself down, will become barely controllable, with previous fatal outcomes. [1]
Two or more FCPCs failing is sufficient evidence that a "faecal fan incident may be occurring" that the risk of deploying them is just not worth it, especially as (pointed out by this parent above) they are effectively optional equipment and the FAA requires you to expect them to be inop to be safe.
What they do save is fuel and time -- taxi time to the terminal, permit the use of high-speed runway turnoffs, etc.
Some of the challenge here was the seconds spent at near landing speed without any braking being performed, as that'll eat up runway distance fast, following the auto brake failure prior to manual braking commencing.