I think there are a number of reasons why these demos are misleading. Putting the keyboard directly on a wooden desk with the feet extended is a great way to encourage resonance, making the sound louder and boosting some sound frequencies more than others. If the microphone is also placed on that desk, then you are recording sound transmitted through wood, not just through the air, which is how you normally hear the sound! Gives a completely different result.
Most recordings are either normalised (boosted as much as possible without distorting) or left at a random level, making comparisons impossible.
And with the best will in the world, if you make a recording to demonstrate the sound, you are going to type abnormally, no matter how hard you try not to.