I think there should be a feature that doesn’t permit one from exceeding the maximum operating speed of the plane one is flying. For example for the 777 it can be capped at Mach .88 etc.
Ground speed varies by winds in a specific location eg if you are flying from New York to London on an A318, even though you are cruising at the right airspeed, you can exceed 500kts groundspeed due to high altitude winds.
The wiki article most likely refers to TAS (true air speed) which is not the same as IAS (indicated air speed) which is more relevant in most cases. TAS is not something we use in Infinite Flight.