Guppy.
Pick any V1 for the day.... add 5kts faster, 5% faster, ect....isn't going to cause a brake failure on an RTO.
If you now want to change back to the subject of runway length available, and the pilot being able to make that judgment having passed V1..
Well I will yet again, repeat, yet again, that with a calculated balance field of say 5000 ft that day...on a ten thousand foot field...and say V1 is established roughly at 2000 -2500 feet...I think it's a safe bet with 7500 feet left over, and overrun beyond, Iowa cornfields beyond, that I will be able to stop the plane without TRs, without hammering the brakes.....
But again, if on that day, with 100 in-definate, blowing snow, forced to fly to the alternate, because this runway only has a GPS approach...you feel free to take the fire, bomb, broken tail up into the soup, pick up some ice...and fly off to your new runway trying to get your broken plane back down safely.
If your assertion is that you don't have any more runway..ever....that all your flights have derated balance field departures calculated into the weeds, forcing you take the emergency up into the air, all the time......that's a policy decision, not because your flying 737s into grass strips in Mongolia. Remember that the next time you fly out of LAX and derate your balanced field to somewhere in San Diego.