Long before we routinely had electric cars, the railway industry started using motors to move trains in diesel-electric locomotives. They used a diesel prime mover to generate electricity used to operate the traction motors. It was found that motors have speed range that they can safely operate at.
Minimum speed was determined by heating effects of high currents with little airflow and maximum speed was determined by how fast the motor's rotating components could spin without flying apart. Minimum speed was specified as a minimum for sustained operation. Lower speeds could be tolerated, but only for a limited amount of time.
A gearbox was used to transmit the motors' rotation to the wheels and differed by type of locomotive. For instance, freight locomotives were typically geared to have a top speed of 65 mph which allowed a lower minimum speed for continuous operation. Passenger locomotives would be geared for a higher top speed as they didn't need to sustain the same minimum speed.
Minimum motor speeds were a greater concern for DC motors, as rotor and/or stator coil burn-outs at low speeds could occur easily. AC motors don't eliminate this, but they are better capable of sustained low speed operations.
Getting back to motors in EVs, the issue of a maximum top speed remains, but issues of stress on the battery are an added concern. In other words, the maximum speed is set for a very good reason. Having said that, I should also add that the maximum speed is not set to a value that, if exceeded by 1 mph, would result in the motor exploding. As is usual engineering practice, a wide margin of error is used.
Consider the last elevator ride you took. That elevator had some maximum load, say 2000 lbs. The elevator will not break off its cable and fall if it is loaded to 2001 lbs (for the example, I'm ignoring the fact that it would not fall if the cable actually broke!). That cable was tested to find that it breaks at something significantly over the 2000 lb rating, possible as much as double. That rating is there to say that if maintained properly, it will continue to carry the stated weight for its expected lifetime. Exceeding the rating by enough will result in immediate failure, but exceeding it by smaller increments will translate in reducing its expected lifetime.
Another example of exceeding ratings is the incandescent light bulb. A bulb may be rated for 120 volts, but if you exceed this, its life will be shortened. If you apply 240 volts to it, it will instantly fail as it does its impression of a photo flash (I've seen this happen). But it will not instantly fail if it were to be powered by 125 volts. In the case of incandescent bulbs, life expectancy reduces by approximately 50% for every 10% the rated voltage is exceeded.
In conclusion, there is a good reason for a limit to the top speed of the motor. Increasing it will reduce life expectancy, but by how much will be something to be determined. Venture at your own risk.