The problem with calling V1 at V1 is that if a moment before V1 there IS an issue, by the time your brain processes the information and action taken by reducing the throttles to idle, you will be in a situation that you are above V1 by the time the abort is initiated. Now all the data goes out the window and you can bet the final report will state that pilot aborted above V1.
V1 calculations take this into consideration.
There is sufficient time to recognize and take the first action of an RTO built into V1, such that you may in fact slightly exceed it during the actions, but still have sufficient runway to stop.
Similarly you may have a failure BEFORE V1, but with insufficient time to start the RTO, and still have enough runway to accelerate to Vr and achieve 35ft over the far threshold.
Being able to react within those time buffers is a skill required to pass your type rating.
Put it this way- if you are going to call V1 5 knots early, why not BUG a speed 5 knots slower and call THAT V1?
Well, the speed we calculate as V1 effectively does just this. Even on what we calculate as a perfectly balanced field, there is "Fat" on either side of V1 for a late RTO decision, or an early lack of detection and "Go" decision.
Adding fat to the fat doesn't make a lot of sense, as you are now in no-mans land. Do you KNOW you can make Vr before the end of the runway if you make an early "Go" decision?
Your Learjet example was an example of not achieving a timely or correct decision- firstly because "Go" is the recommended decision if you lose tires (as you also lose braking ability) and "What have we got" is not an appropriate question at any time during a takeoff roll!!
Where they between V1-5 and V1 when the tires blew?