It isn’t as simple as adding more runway, there are other factors that must be considered. All aircraft tires have speed limits for one. Also beyond having enough distance to takeoff aircraft must also have enough braking power to stop an aircraft within the runway length from the takeoff decision speed. An aircrafts braking system will have a hard time stopping the aircraft at such high speeds as well as handle the associated thermal energy created.

The aircraft would have a climb performance penalty meaning it wouldn’t be able to achieve the necessary altitude/speed requirements once off the ground.

I don’t think there is anyway an aircraft can “get away with it” if it hasn’t been flight tested.

Yes, very true but I was talking theoretically. The practical limitations may well put a different outlook on things.